Segi Tiga

/*
    Task    : _example
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 08 January 2023 [10:44]
*/
#include<bits/stdc++.h>
using namespace std;
char a[260];
int dp[260][260][3];
int res[3][3] = {2,1,0,2,1,1,1,2,1};
bool recur(int l,int r,int target){
    if(l == r)                  return (a[l] - '0' == target);
    if(dp[l][r][target] != -1)  return dp[l][r][target];
    int mn = 1e9;
    for(int k=l;k<r;k++){
        for(int i=0;i<=2;i++){
            for(int j=0;j<=2;j++){
                if(res[i][j] != target) continue;
                if(recur(l,k,i) && recur(k+1,r,j))
                    return dp[l][r][target] = 1;
            }
        }
    }
    return dp[l][r][target] = 0;
}
int main(){
    int q=20;
    while(q--){
        int n;
        scanf("%d %s",&n,a+1);
        memset(dp,-1,sizeof dp);
        if(recur(1,n,0))    printf("yes\n");
        else                printf("no\n");
    }
    return 0;
}