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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define ll long long
  5. #define ul unsigned long long
  6.  
  7. ll mod = 1e9+7;
  8. const int N = 1e3+5;
  9. int MOD = 998244353;
  10. int bit[200000];
  11. int n, m;
  12. //vector<int> adj[N];
  13. int a[N][N];
  14. bool visit[N][N];
  15. int sX[] = {0, 0, 1, -1};
  16. int sY[] = {1, -1, 0, 0};
  17. int dem = 1;
  18. void nhap(){
  19. 	cin >> n >> m;
  20. 	for(int i= 1 ; i <= n ;  i++){
  21. 		for(int j= 1; j <= m ; j++){
  22. 			cin >> a[i][j];
  23. 		}
  24. 	}
  25. }
  26. void bfs(int sx, int sy) { 
  27.     queue < pair <int, int> > q;
  28.     q.push({sx, sy});
  29.     visit[sx][sy] = true;
  30.     while (!q.empty()) {
  31.         int x = q.front().first;
  32.         int y = q.front().second;
  33.         q.pop();
  34.  
  35.         for (int i = 0; i < 4; ++i) {
  36.             int u = x + sX[i];
  37.             int v = y + sY[i];
  38.  
  39.             if (u > n || u < 1) continue;
  40.             if (v > m || v < 1) continue;
  41.  
  42.             if (a[u][v] == 0 && !visit[u][v]) {
  43.                 visit[u][v] = true;
  44.                 q.push({u, v});
  45.                 dem++;
  46.             }
  47.         }
  48.     }
  49. }
  50. int main() {
  51. 	//freopen("CSBN.INP", "r", stdin);
  52. 	//freopen("CSBN.OUT", "w", stdout);
  53. 	ios_base::sync_with_stdio(0);
  54. 	cin.tie(0);
  55. 	cout.tie(0);
  56.  
  57.     nhap();
  58.     if(a[1][1] == 1){
  59.     	cout << -1;
  60. 	}
  61. 	else{
  62.     bfs(1,1);
  63.  
  64. 	cout << dem;
  65. 	}
  66. }
  67.  
Success #stdin #stdout 0.01s 5316KB
comments (?)
stdin
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4 5
01000
01010
00010
11010
stdout
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17
https://ideone.com/B3kuGe
language:
C++14 (clang 8.0)
created:
4 days ago
visibility:
public

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