OJ Board

why wa? #include<iostream>
#include<stdio.h>
#include<queue>
#include<string.h>
using namespace std;
int n;
char pic[30][30];
void bfs(int i, int j)
{
queue<int> Q;
int u,v,w;
Q.push(i*n+j);
pic[i][j]='0';
while(!Q.empty())
{
u=Q.front();
v=u/n;
w=u%n;
for(int a=v-1;a<=v+1;a++)
{
if(a<0 ...