Submission #1417481

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Source Code Expand

import java.util.*;

public class Main{
    int[] DP = new int[100];
    String s;
    int N;
    public Main(int N, String s){
	for(int i=0;i<N;i++) DP[i]=-1;
	this.N = N;
	this.s = s;
    }

    public int min(int a, int b){
	if(a<b) return a;
	return b;
    }

    public int count(int n){
	if(n==N) return 0;
	if(DP[n-1]!=-1) return DP[n-1]; 
	if(n>N-4){
	    if(s.charAt(n-1)=='.') return DP[n-1]=0;
	    return DP[n-1]=1;
	}
	int c1, c2, c3, ans;
	c1 = count(n+1);
	c2 = count(n+2);
	c3 = count(n+3);
	ans = min(c1,min(c2,c3));
	if(s.charAt(n-1)=='X') ans++;
	return DP[n-1]=ans;
    }

    public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
	int N = sc.nextInt();
	String s = sc.next();
	Main m = new Main(N,s);
	int ans = m.count(1);
	System.out.println(ans);
    }
}

Submission Info

Judge Result