求调，CF Wrong answer on test 6

#include<iostream>
#include<queue>
using namespace std;
#define int long long
int a[1005][1005],dis[1005][1005];
bool l[1005][1005];
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
struct node{
    int x,y;
}x,z;
queue<node> q;

signed main(){
    //freopen("game.in","r",stdin);
    //freopen("game.out","w",stdout);
    ios::sync_with_stdio(0);
    int n,m,w;
    char c;
    cin>>n>>m>>w;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>c;
            a[i][j]=c-'0';
        }
    }
    for(int i=0;i<=n+1;i++){
        a[i][0]=2;
        a[n+1][i]=2;
    }
    for(int i=0;i<=m+1;i++){
        a[0][i]=2;
        a[i][m+1]=2;
    }
    for(int i=1;i<=n;i++){
    	for(int j=1;j<=m;j++){
    		dis[i][j]=1e9;
		}
	}
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            int flag=0;
            for(int d=0;d<4;d++){
                if(a[i+dx[d]][j+dy[d]]==a[i][j]){
                    flag=1;
                    break;
                }
            }
            if(flag==1){
            	l[i][j]=1;
            	dis[i][j]=0;
            	x.x=i;
            	x.y=j;          	
            	q.push(x);
			} 
        }
    }
    while(!q.empty()){
    	int x=q.front().x;
    	int y=q.front().y;
    	q.pop();
    	for(int i=0;i<4;i++){
    		int nx=x+dx[i];
    		int ny=y+dy[i];
    		if(nx<1 || nx>n || ny<1 || ny>m) continue;
    		if(!l[nx][ny]){
    			z.x=nx;
    			z.y=ny;
    			if(dis[nx][ny]>dis[x][y]+1){
    				dis[nx][ny]=dis[x][y]+1;
    				q.push(z);
				}
			}
		}
	}
    int x,y,t;
    while(w--){
        cin>>x>>y>>t;
        if(t<dis[x][y]) cout<<a[x][y];
        else cout<<(a[x][y]+(t-dis[x][y])%2)%2;
        cout<<'\n';
    }
    return 0;
}