https://www.luogu.org/problem/P1141
思路：找到每一个连通块，不同连通块的标记不同，给标记赋值成该连通块的数量
1 // luogu-judger-enable-o2 2 #include <cstdio> 3 #include <iostream> 4 #include <algorithm> 5 #include <cmath> 6 #include <queue> 7 #include <vector> 8 #include <cstring> 9 #include <map> 10 #define mem(a) memset(a,0,sizeof(a)) 11 using namespace std; 12 typedef long long ll; 13 const int maxn = 200005; 14 const ll INF = 0x3f3f3f3f3f; 15 int dir[8][2]= {2,1,1,2,-2,1,-1,2,2,-1,1,-2,-2,-1,-1,-2}; 16 int dir2[4][2]= {0,1,0,-1,1,0,-1,0}; 17 bool flag; 18 int vis[1005][1005],sum[1000005]; 19 int n,m,countt,num; 20 string s[1005]; 21 void dfs(int x,int y){ 22 countt++; 23 vis[x][y] = num; 24 for(int i = 0; i < 4; i++){ 25 int fx = x + dir2[i][0],fy = y + dir2[i][1]; 26 if(fx >=0 && fx < n && fy >=0 && fy < n && !vis[fx][fy] && s[x][y] == '0' && s[fx][fy] == '1') 27 dfs(fx,fy); 28 if(fx >=0 && fx < n && fy >=0 && fy < n && !vis[fx][fy] && s[x][y] == '1' && s[fx][fy] == '0') 29 dfs(fx,fy); 30 } 31 } 32 int main() 33 { 34 35 while(cin >> n >> m){ 36 mem(vis); 37 mem(sum); 38 num = 1; 39 for(int i = 0; i < n; i++) 40 cin >> s[i]; 41 for(int i = 0; i < n; i++){ 42 for(int j = 0; j < n; j++){ 43 if(vis[i][j] == 0) 44 { 45 countt = 0; 46 vis[i][j] = num; 47 dfs(i,j); 48 sum[num] = countt; 49 //cout << sum[num] << endl; 50 num++; 51 } 52 } 53 } 54 int x, y; 55 //for(int i = 1; i < num; i++) cout << sum[i] << endl; 56 for(int i = 0; i < m; i++){ 57 cin >> x >> y; 58 cout << sum[vis[x-1][y-1]] << endl; 59 } 60 } 61 return 0; 62 }