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Commit 36eba57

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2 files changed

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‎src/LeetcodeQuestions/HouseRobber.java

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package LeetcodeQuestions;
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// https://leetcode.com/problems/house-robber/
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// https://leetcode.com/problems/house-robber-ii/
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public class HouseRobber {
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// linear..
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public static int houserob(int nums[]) {
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if (nums.length == 0) {
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return 0;
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}
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int[] dp = new int[nums.length + 1];
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dp[0] = 0;
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dp[1] = nums[0];
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for (int i = 2; i < nums.length + 1; i++) {
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dp[i] = Math.max(dp[i - 1], nums[i - 1] + dp[i - 2]);
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}
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return dp[nums.length];
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}
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// when houses are in circular fashion..
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public static int houserobCircular(int nums[]) {
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if (nums.length == 0)
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return 0;
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if (nums.length == 1)
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return nums[0];
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int maxExcludeFirst = helper(nums, 1, nums.length);
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int maxExcludeLast = helper(nums, 0, nums.length - 1);
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return Math.max(maxExcludeFirst, maxExcludeLast);
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}
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public static int helper(int[] nums, int start, int end) {
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int prevMax = 0;
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int currentMax = 0;
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for (int i = start; i < end; i++) {
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int newMax = Math.max(currentMax, nums[i] + prevMax);
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prevMax = currentMax;
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currentMax = newMax;
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}
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return currentMax;
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}
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public static void main(String[] args) {
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}
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}

‎src/LeetcodeQuestions/uniquePath.java

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@@ -6,23 +6,120 @@
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// https://leetcode.com/problems/unique-paths-ii/
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public class uniquePath {
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public static boolean uniquePathone() {
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//O(M*N)
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public static int uniquePathwithObstacles(int arr[][]) {
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int r = arr.length;
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int c = arr[0].length;
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if (arr[0][0] == 1) {
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return 0;
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}
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arr[0][0] = 1;
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for (int i = 1; i < r; i++) {
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arr[i][0] = (arr[i][0] == 0 && arr[i - 1][0] == 1) ? 1 : 0;
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}
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for (int i = 1; i < r; i++) {
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arr[0][i] = (arr[0][i] == 0 && arr[0][i - 1] == 1) ? 1 : 0;
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}
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for (int i = 1; i < r; i++) {
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for (int j = 1; j < c; j++) {
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if (arr[i][j] == 0) {
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arr[i][j] = arr[i - 1][j] + arr[i][j - 1];
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} else {
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arr[i][j] = 0;
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}
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}
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}
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return arr[r - 1][c - 1];
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}
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// Unique paths without any obstacles recursive and dp solution ...
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public int uniquePaths(int m, int n) {
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return solve(0, 0, m, n);
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}
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// recursive
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public int solve(int i, int j, int m, int n) {
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if (i >= m || j >= n)
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return 0;
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if (i == m - 1 && j == n - 1)
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return 1;
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return solve(i + 1, j, m, n) + solve(i, j + 1, m, n);
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}
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int[][] dp = new int[101][101];
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// dp ...
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public int uniquePathsDP(int m, int n) {
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for (int i = 0; i < m; i++)
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for (int j = 0; j < n; j++)
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dp[i][j] = -1;
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return solvedp(0, 0, m, n);
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}
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public int solvedp(int i, int j, int m, int n) {
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if (i >= m || j >= n)
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return 0;
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if (i == m - 1 && j == n - 1)
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return 1;
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if (dp[i][j] != -1)
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return dp[i][j];
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return dp[i][j] = solve(i + 1, j, m, n) + solve(i, j + 1, m, n);
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}
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// convert into 1d dp method...
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static int numberOfPaths(int m, int n) {
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// Create a 1D array to store results of subproblems
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int[] dp = new int[n];
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dp[0] = 1;
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for (int i = 0; i < m; i++) {
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for (int j = 1; j < n; j++) {
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dp[j] += dp[j - 1];
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}
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}
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return dp[n - 1];
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}
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// using combinatorics..
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static int numberOfPaths2(int m, int n) {
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// We have to calculate m+n-2 C n-1 here
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// which will be (m+n-2)! / (n-1)! (m-1)!
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int path = 1;
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for (int i = n; i < (m + n - 1); i++) {
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path *= i;
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path /= (i - n + 1);
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}
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return path;
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}
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public static void main(String[] args) {
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int arr[][]={{0,0,0},{0,1,0},{0,0,0}};
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int arr[][] = {{0,0, 0},{0,1, 0},{0,0, 0}};
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System.out.println();
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