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Learning DP

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Lines changed: 46 additions & 0 deletions

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	`1`	`+package Codeforces;`
	`2`	`+`
	`3`	`+import java.io.*;`
	`4`	`+import java.util.ArrayList;`
	`5`	`+`
	`6`	`+public class CutRibbon {`
	`7`	`+ static ArrayList<Integer> ls;`
	`8`	`+ static int[] dp;`
	`9`	`+ public static void main(String[] args)throws IOException {`
	`10`	`+`
	`11`	`+ BufferedReader br = new BufferedReader(new InputStreamReader(System.in));`
	`12`	`+`
	`13`	`+ String[] s = br.readLine().split(" ");`
	`14`	`+ int n = Integer.parseInt(s[0]);`
	`15`	`+ int a = Integer.parseInt(s[1]);`
	`16`	`+ int b = Integer.parseInt(s[2]);`
	`17`	`+ int c = Integer.parseInt(s[3]);`
	`18`	`+ ls = new ArrayList<>();`
	`19`	`+ ls.add(a);`
	`20`	`+ ls.add(b);`
	`21`	`+ ls.add(c);`
	`22`	`+`
	`23`	`+`
	`24`	`+ dp = new int[n + 1];`
	`25`	`+ for(int i=1; i<=n; i++){`
	`26`	`+ if(i%a == 0 \|\| i%b == 0 \|\| i%c == 0)dp[i] = 1; //Initialize the dp values to 1 for all the multiples of a , b, c`
	`27`	`+ } //since this are the only values we will use`
	`28`	`+ int ans = ribbonCutting(n, ls); //and this pieces can finally reduce to smaller a, b, c values.`
	`29`	`+ System.out.println(ans);`
	`30`	`+`
	`31`	`+ }`
	`32`	`+`
	`33`	`+ private static int ribbonCutting(int n, ArrayList<Integer> ls){`
	`34`	`+`
	`35`	`+ for(int i=1; i<=n; i++){`
	`36`	`+ for(int j:ls){`
	`37`	`+ if(i-j >= 0 && dp[i-j] != 0){`
	`38`	`+ dp[i] = Math.max(dp[i], dp[i-j]+1);`
	`39`	`+ }`
	`40`	`+ }`
	`41`	`+ }`
	`42`	`+`
	`43`	`+`
	`44`	`+ return dp[n];`
	`45`	`+ }`
	`46`	`+}`

Lines changed: 32 additions & 0 deletions

Original file line number	Diff line number	Diff line change
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	`1`	`+package Codeforces;`
	`2`	`+import java.io.*;`
	`3`	`+import java.util.Arrays;`
	`4`	`+`
	`5`	`+public class KefaandFirstSteps {`
	`6`	`+ public static void main(String[] args)throws IOException {`
	`7`	`+ BufferedReader br = new BufferedReader(new InputStreamReader(System.in));`
	`8`	`+`
	`9`	`+ int n = Integer.parseInt(br.readLine());`
	`10`	`+ String[] s = br.readLine().split(" ");`
	`11`	`+ int[] a = new int[s.length];`
	`12`	`+`
	`13`	`+ for(int i=0; i<s.length; i++)a[i] = Integer.parseInt(s[i]);`
	`14`	`+ int[] dp = new int[s.length];`
	`15`	`+ Arrays.fill(dp,1);`
	`16`	`+`
	`17`	`+ int ans = longestSubsegment(a,dp);`
	`18`	`+ System.out.println(ans);`
	`19`	`+ }`
	`20`	`+`
	`21`	`+ private static int longestSubsegment(int[] a, int[] dp){`
	`22`	`+ int max = 1;`
	`23`	`+ for(int i=1; i<a.length; i++){`
	`24`	`+ if(a[i] >= a[i-1]){`
	`25`	`+ dp[i] = dp[i-1] + 1;`
	`26`	`+ }`
	`27`	`+ if(max < dp[i])max = dp[i];`
	`28`	`+ }`
	`29`	`+`
	`30`	`+ return max;`
	`31`	`+ }`
	`32`	`+}`

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