【HDOJ】3316 Mine sweeping

简单BFS。

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <queue>
using namespace std;

#define MAXN 105

typedef struct node_t {
    int x, y;
    node_t() {}
    node_t(int xx, int yy) {
        x = xx; y = yy;
    }
} node_t;

char map[MAXN][MAXN];
char ans[MAXN][MAXN];
bool visit[MAXN][MAXN];
int dir[8][2] = {
    {-1,0},{1,0},{0,1},{0,-1},
    {1,1},{1,-1},{-1,1},{-1,-1}
};
node_t s;
int n;

bool check(int x, int y) {
    return x<0 || x>=n || y<0 || y>=n;
}

void bfs() {
    int i, j, k, tmp;
    int x, y, v;
    int xx[8], yy[8], m;
    queue<node_t> Q;
    node_t nd;
    
    memset(visit, false, sizeof(visit));
    memset(ans, '.', sizeof(ans));
    visit[s.x][s.y] = true;
    for (i=0; i<n; ++i)
        ans[i][n] = '';
    Q.push(s);
    
    while (!Q.empty()) {
        nd = Q.front();
        Q.pop();
        v = m = 0;
        for (i=0; i<8; ++i) {
            x = nd.x + dir[i][0];
            y = nd.y + dir[i][1];
            if (check(x, y))
                continue;
            xx[m] = x;
            yy[m] = y;
            ++m;
            if (map[x][y] == 'X')
                ++v;
        }
        ans[nd.x][nd.y] = v+'0';
        if (v == 0) {
            for (i=0; i<m; ++i) {
                if (!visit[xx[i]][yy[i]]) {
                    visit[xx[i]][yy[i]] = true;
                    Q.push(node_t(xx[i], yy[i]));
                }
            }
        }
    }
}

int main() {
    int i, j;

#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif    
    
    while (scanf("%d", &n) != EOF) {
        for (i=0; i<n; ++i)
            scanf("%s", map[i]);
        scanf("%d %d", &s.x, &s.y);
        
        if (map[s.x][s.y] == 'X') {
            printf("it is a beiju!

");
        } else {
            bfs();
            for (i=0; i<n; ++i)
                printf("%s
", ans[i]);
            printf("
");
        }
    }
    
    return 0;
}