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Commit 8252d54

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2 parents 3aab10e + 906fd25 commit 8252d54

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‎BOJ/1000-5000번/DH_1052.java‎

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import java.io.*;
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import java.util.*;
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/*
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* 물병
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*/
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public class DH_1052 {
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public static void main(String[] args) throws Exception {
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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StringTokenizer st = new StringTokenizer(br.readLine());
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int n = Integer.parseInt(st.nextToken());
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int k = Integer.parseInt(st.nextToken());
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int answer = 0;
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while(Integer.bitCount(n) > k) {
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answer += 1;
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n += 1;
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}
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System.out.println(answer);
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}
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}

‎BOJ/1000-5000번/DH_1761.java‎

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import java.io.*;
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import java.util.*;
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/*
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* 정점들의 거리
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*/
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public class DH_1761 {
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static class Node {
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int e, w;
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public Node(int e, int w) {
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this.e = e;
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this.w = w;
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}
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}
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static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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static StringBuilder sb = new StringBuilder();
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static StringTokenizer st;
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static int N;
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static ArrayList<Node> adj[];
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static int[] depth, p, dis;
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public static void main(String[] args) throws Exception {
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initInput();
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solution();
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}
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static void solution() throws Exception {
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bfs();
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getDis();
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}
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static void getDis() throws Exception {
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int M = Integer.parseInt(br.readLine());
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for(int i = 0; i < M; i++) {
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st = new StringTokenizer(br.readLine());
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int a = Integer.parseInt(st.nextToken());
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int b = Integer.parseInt(st.nextToken());
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// a, b의 최소공통조상 구하고, 두 점 간 사이 구하기
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sb.append(LCA(a, b)).append("\n");
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}
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System.out.print(sb);
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}
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static long LCA(int a, int b) {
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// result = (루트 ~ a) + (루트 ~ b) - 2 * (루트 ~ 최소공통조상)
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long result = dis[a] + dis[b];
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int depthA = depth[a];
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int depthB = depth[b];
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// 무조건 a가 depth가 작도록
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if(depthB < depthA) {
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int tmp = a;
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a = b;
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b = tmp;
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}
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int diffDis = Math.abs(depthA - depthB);
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// 깊이 맞추기
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for(int i = 0; i < diffDis; i++) b = p[b];
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while(a != b) {
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a = p[a];
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b = p[b];
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}
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return result - 2 * dis[a];
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}
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static void bfs() {
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boolean[] v = new boolean[N + 1];
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Queue<Node> q = new ArrayDeque<>();
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q.add(new Node(1, 0));
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v[1] = true;
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while(!q.isEmpty()) {
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Node current = q.poll();
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for(Node next: adj[current.e]) {
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if(v[next.e]) continue;
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p[next.e] = current.e;
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depth[next.e] = depth[current.e] + 1;
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dis[next.e] = dis[current.e] + next.w;
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v[next.e] = true;
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q.add(next);
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}
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}
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}
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static void initInput() throws Exception {
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br = new BufferedReader(new InputStreamReader(System.in));
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N = Integer.parseInt(br.readLine());
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adj = new ArrayList[N + 1];
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depth = new int[N + 1];
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dis = new int[N + 1];
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p = new int[N + 1];
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for(int i = 0; i < adj.length; i++) adj[i] = new ArrayList<>();
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for(int i = 0; i < N - 1; i++) {
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st = new StringTokenizer(br.readLine());
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int s = Integer.parseInt(st.nextToken());
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int e = Integer.parseInt(st.nextToken());
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int w = Integer.parseInt(st.nextToken());
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adj[s].add(new Node(e, w));
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adj[e].add(new Node(s, w));
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}
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}
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}

‎BOJ/1000-5000번/HW_1052.java‎

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import java.io.*;
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import java.util.*;
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// 시간복잡도 : Integer.bitCount O(log N) * K 물병 개수
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// 상점에서 사야하는 물병의 최솟값
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public class HW_1052 {
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public static void main(String[] args) throws IOException {
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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StringTokenizer st = new StringTokenizer(br.readLine());
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int N = Integer.parseInt(st.nextToken());
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int K = Integer.parseInt(st.nextToken());
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int ans = 0;
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while(true) {
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int cnt = Integer.bitCount(N); // 2^n 리터 단위로 병 합칠 수 있음
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if(cnt<=K) { // K개를 넘으면 멈춤
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break;
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}
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N++; // 물병 사기
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ans++; //
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}
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System.out.println(ans);
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}
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}

‎BOJ/1000-5000번/HW_1761.java‎

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import java.io.*;
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import java.util.*;
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// 시간 복잡도 : O(N + M logN)
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public class HW_1761 {
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static int N, M, maxDepth;
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static List<int[]>[] tree;
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static int[] depth; // 깊이 저장
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static int[][] parent; // 부모 노드 저장
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static int[] dist; // 거리 저장
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public static void main(String[] args) throws IOException {
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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StringTokenizer st;
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N = Integer.parseInt(br.readLine());
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maxDepth = (int) (Math.log(N) / Math.log(2)) + 1;
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// 트리 초기화
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tree = new ArrayList[N+1];
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for(int i=1; i<=N; i++) {
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tree[i] = new ArrayList<>();
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}
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// 간선 정보 입력
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for(int i=0; i<N-1; i++) {
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st = new StringTokenizer(br.readLine());
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int u = Integer.parseInt(st.nextToken());
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int v = Integer.parseInt(st.nextToken());
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int w = Integer.parseInt(st.nextToken()); // 거리
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tree[u].add(new int[] {v, w});
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tree[v].add(new int[] {u, w});
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}
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depth = new int[N+1];
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dist = new int[N+1];
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parent = new int[N+1][maxDepth];
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Arrays.fill(depth, -1);
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// DFS
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depth[1] = 0;
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dfs(1, 0);
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// 부모 테이블
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for(int d=1; d<maxDepth; d++) {
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for(int i=1; i<=N; i++) {
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if(parent[i][d-1] != 0) { // 이전 단계에 부모가 존재할 경우
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parent[i][d] = parent[parent[i][d-1]][d-1];
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}
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}
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}
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M = Integer.parseInt(br.readLine());
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// 공통 조상 구하기
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for(int i=0; i<M; i++) {
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st = new StringTokenizer(br.readLine());
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int u = Integer.parseInt(st.nextToken());
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int v = Integer.parseInt(st.nextToken());
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int lca = LCA(u, v);
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int distance = dist[u] + dist[v] - 2 * dist[lca];
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System.out.println(distance);
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}
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}
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static void dfs(int node, int d) {
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for(int[] edge: tree[node]) {
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int next = edge[0];
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int weight = edge[1];
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if(depth[next] == -1) { // 방문하지 않은 노드라면
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depth[next] = depth[node] + 1; // 깊이 설정
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dist[next] = dist[node] + weight; // 루트에서 거리 계산
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parent[next][0] = node; // 바로 위 부모 노드 설정
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dfs(next, d+1); // 다음 노드 탐색
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}
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}
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}
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static int LCA(int u, int v) {
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if(depth[u] < depth[v]) {
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int temp = u;
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u = v;
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v = temp;
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}
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// 깊이를 맞추기
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for(int i=maxDepth-1; i>=0; i--) {
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if(depth[u] - (1<<i) >= depth[v]) {
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u = parent[u][i];
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}
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}
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// 공통 조상 찾기
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if(u==v)
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return u;
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// 같은 조상이 나올 때까지 한 칸씩 올리기
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for(int i=maxDepth-1; i>=0; i--) {
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if(parent[u][i] != parent[v][i]){
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u = parent[u][i];
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v = parent[v][i];
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}
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}
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return parent[u][0];
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}
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}

‎BOJ/1000-5000번/JW_1052.java‎

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import java.io.BufferedReader;
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import java.io.InputStreamReader;
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import java.util.StringTokenizer;
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public class JW_1052 {
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public static void main(String[] args) throws Exception {
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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StringTokenizer st = new StringTokenizer(br.readLine());
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int n = Integer.parseInt(st.nextToken());
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int k = Integer.parseInt(st.nextToken());
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int cnt = 0;
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// k개로 옮기지 못하는 경우
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// 2개씩 합쳐서 옮길 수 없는 경우 즉, 2^m의 조합의 수 > k
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while (Integer.bitCount(n) > k) {
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// 최소한의 수를 더하여 비트 줄이기
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cnt += Integer.lowestOneBit(n);
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n += Integer.lowestOneBit(n);
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}
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System.out.println(cnt);
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}
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}

‎BOJ/1000-5000번/JW_1761.java‎

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import java.util.ArrayDeque;
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import java.util.ArrayList;
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import java.util.Deque;
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public class JW_1761 {
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static int n;
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static ArrayList<ArrayList<Node>> tree = new ArrayList<>();
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static int[] depth, dist;
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static int[] parent;
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static class Node {
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int v;
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int w;
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Node(int v, int w) {
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this.v = v;
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this.w = w;
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}
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}
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public static void main(String[] args) throws Exception {
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n = read();
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parent = new int[n + 1];
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depth = new int[n + 1];
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dist = new int[n + 1];
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for (int i = 0; i < n + 1; i++)
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tree.add(new ArrayList<>());
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for (int i = 0; i < n - 1; i++) {
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int u = read(), v = read(), w = read();
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tree.get(u).add(new Node(v, w));
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tree.get(v).add(new Node(u, w));
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}
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bfs();
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StringBuilder sb = new StringBuilder();
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int t = read();
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while (t-- > 0) {
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int a = read(), b = read();
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sb.append(LCA(a, b)).append("\n");
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}
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System.out.println(sb);
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}
43+
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static void bfs() {
45+
boolean[] visited = new boolean[n + 1];
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Deque<Node> dq = new ArrayDeque<>();
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dq.offer(new Node(1, 0));
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visited[1] = true;
49+
while (!dq.isEmpty()) {
50+
Node cur = dq.poll();
51+
for (Node next : tree.get(cur.v)) {
52+
if (visited[next.v])
53+
continue;
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parent[next.v] = cur.v;
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depth[next.v] = depth[cur.v] + 1;
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dist[next.v] = dist[cur.v] + next.w;
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visited[next.v] = true;
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dq.offer(next);
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}
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}
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}
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static long LCA(int a, int b) {
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long result = dist[a] + dist[b];
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int depthA = depth[a];
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int depthB = depth[b];
67+
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if (depthB < depthA) {
69+
int tmp = a;
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a = b;
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b = tmp;
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}
73+
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int diff = Math.abs(depthA - depthB);
75+
for (int i = 0; i < diff; i++)
76+
b = parent[b];
77+
78+
while (a != b) {
79+
a = parent[a];
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b = parent[b];
81+
}
82+
return result - 2 * dist[a];
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}
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private static int read() throws Exception {
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int c, n = System.in.read() & 15;
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while ((c = System.in.read()) >= 48)
88+
n = (n << 3) + (n << 1) + (c & 15);
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if (c == 13)
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System.in.read();
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return n;
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}
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}

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