全RE了，求大佬看看

#include<bits/stdc++.h>

using namespace std;

const int N = 410;

int dist[N][N];
int n, m, x, y;
typedef pair<int, int> PII;
queue <PII> q;
int dx[] = {2, 2, 1, 1, -1, -1, -2, -2};
int dy[] = {1, -1, 2, -2, 2, -2, 1, -1};

int bfs(int x1, int y1){
    memset(dist, -1, sizeof dist);
    dist[x1][y1] = 0;
    q.push({x1, y1});
    while(q.size()){
        PII t = q.front();
        q.pop();
        for(int i = 0; i < 8; i ++ ){
            int a = t.first + dx[i], b = t.second + dy[i];
            if(dist[a][b] != -1) continue;
            if(a < 1 || a > n || b < 1 || b > m) continue;
            dist[a][b] = dist[t.first][t.second] + 1;
            q.push({a, b});
            
        }
    }
}

int main(){
    scanf("%d %d %d %d", &n, &m, &x, &y);
    bfs(x, y);
    for(int i = 1; i <= n; i ++ ){
        for(int j = 1; j <= m; j ++ ){
            printf("%-5d", dist[i][j]);
        }
        printf("\n");
    }
}