【Codeforces 598D】Igor In the Museum

【链接】 我是链接,点我呀:)

【题意】

题意

【题解】

同一个联通块里面答案都一样。
把每个联通块的答案都算出来 然后赋值就好

【代码】

#include <bits/stdc++.h>
using namespace std;
const int N = 1000;

int n,m,k;
int dx[4] = {0,0,1,-1};
int dy[4] = {1,-1,0,0};
char s[N+10][N+10];
bool bo[N+10][N+10];
int ans[N+10][N+10];
pair<int,int> dl[N*N+10];
int head,tail;

int main(){
    ios::sync_with_stdio(0),cin.tie(0);
    cin >> n >> m >> k;
    for (int i = 1;i <= n;i++) cin >> (s[i]+1);
    for (int i = 1;i <= n;i++)
        for (int j = 1;j <= m;j++)
            if (!bo[i][j] && s[i][j]=='.'){
                head = 1,tail = 1;
                dl[head] = {i,j};
                int cnt = 0;
                bo[i][j] = true;
                while (head<=tail){
                    int x = dl[head].first,y = dl[head].second;
                    head++;
                    for (int l = 0;l < 4;l++){
                        int tx = x + dx[l],ty = y + dy[l];
                        if (tx>=1 && tx <= n && ty>=1 && ty<=m){
                            if (!bo[tx][ty] && s[tx][ty]=='.'){
                                bo[tx][ty] = true;
                                tail++;
                                dl[tail].first = tx;
                                dl[tail].second = ty;
                            }else if (s[tx][ty]=='*'){
                                cnt++;
                            }
                        }
                    }
                }
                for (int i = 1;i <= tail;i++){
                    ans[dl[i].first][dl[i].second] = cnt;
                }
            }
    for (int i = 1;i <= k;i++){
        int x,y;
        cin >> x >> y;
        cout<<ans[x][y]<<endl;
    }
	return 0;
}