为啥最后一个点挂了啊？据说那个点是卡memset的，但是我这WA是什么鬼？有大佬帮忙找一下Bug吗？

#include <iostream>
using namespace std;
#define MAX_N 100010
#define int long long
int T;
signed main(){
    cin >> T;
    while(T--){
        int n,ans = 0;
        char map[21][MAX_N];
        cin >> n;
        for(int i = 1;i <= 2;i++)
            for(int j = 1;j <= n;j++)
                cin >> map[i][j];
        for(int j = 1;j <= n;j++){
            for(int i = 1;i <= 2;i++){
                if(map[i][j] == '1'){
                    if(i == 1){
                        if(map[i][j-1] == '0')
                            map[i][j-1] = map[i][j] = '-';
                        else if(map[i+1][j] == '0')
                            map[i+1][j] = map[i][j] = '-';
                        else if(map[i][j+1] == '0')
                            map[i][j+1] = map[i][j] = '-';
                        else
                            ans = -1;
                    }
                    else{
                        if(map[i][j-1] == '0')
                            map[i][j-1] = map[i][j] = '-';
                        else if(map[i-1][j] == '0')
                            map[i-1][j] = map[i][j] = '-';
                        else if(map[i][j+1] == '0')
                            map[i][j+1] = map[i][j] = '-';
                        else
                            ans = -1;
                    }
                }
            }
        }
        if(ans == -1) cout << "++" << endl;
        else cout << "RP" << endl;
    }
    return 0;
}