NYOJ ~ 92 ~ 图像有效区域（BFS+预处理）

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1500;
struct node
{
int x,y;
}NOW,NEXT;
int W,H,MAP[MAXN][MAXN],dir[4][2] = {{1,0},{0,1},{-1,0},{0,-1}};
bool vis[MAXN][MAXN];
void bfs()
{
memset(vis,0,sizeof(vis));
NOW.x = 0; NO
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W.y = 0;
queue<node> q;
q.push(NOW);
while(!q.empty())
{
NOW = q.front();
q.pop();
for(int i = 0; i < 4; i++)
{
int X = NOW.x + dir[i][0], Y = NOW.y + dir[i][1];
if(X >= 0 && Y >= 0 && X <= H + 1 && Y <= W + 1 && vis[X][Y] == false && MAP[X][Y] != 0)
{
vis[X][Y] = true;
MAP[X][Y] = 0;
NEXT.x = X; NEXT.y = Y;
q.push(NEXT);
}
}
}
}
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
memset(MAP,1,sizeof(MAP));
scanf("%d%d",&W,&H);
for(int i = 1; i <= H; i++)
{
for(int j = 1; j <= W; j++)
{
scanf("%d",&MAP[i][j]);
}
}
bfs();
for(int i = 1; i <= H; i++)
{
for(int j = 1; j <= W; j++)
{
printf("%d ",MAP[i][j]);
}
printf("\n");
}
}
return 0;
}