RE0pts 求原因

#include <bits/stdc++.h>
using namespace std;
int n;
string s="yizhong";
char mapp[110][110];
int mark[110][110];
int dx[]={0,-1,-1,-1, 0, 0, 1, 1, 1};
int dy[]={0,-1, 0, 1,-1, 1,-1, 0, 1};
int dfs(int x,int y,int dir,int stp){
	if (stp==6){
		return 1;
	}
	int nx=x+dx[dir],ny=y+dy[dir];
	if (nx>=1&&nx<=n&&ny>=1&&ny<=n&&mapp[nx][ny]==s[stp+1]&&dfs(nx,ny,dir,stp+1)){
		mark[nx][ny]=1;
		return 1;
	}
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin>>n;
	for (int i=1;i<=n;i++){
		for (int j=1;j<=n;j++){
			cin>>mapp[i][j];
		}
	}
	for (int i=1;i<=n;i++){
		for (int j=1;j<=n;j++){
			for (int k=1;k<=8;k++){
				if (mapp[i][j]=='y'&&dfs(i,j,k,0)){
					mark[i][j]=1;
				}
			}
		}
	}
	for (int i=1;i<=n;i++){
		for (int j=1;j<=n;j++){
			cout<<(mark[i][j]?mapp[i][j]:'*');
		}
		cout<<"\n";
	}
	return 0;
}