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  1. // iostream is too mainstream
  2. #include <cstdio>
  3. // bitch please
  4. #include <iostream>
  5. #include <vector>
  6. #include <set>
  7. #include <map>
  8. #include <string>
  9. #include <queue>
  10. #include <stack>
  11. #include <algorithm>
  12. #include <cmath>
  13. #include <iomanip>
  14. #define dibs reserve
  15. #define OVER9000 1234567890
  16. #define patkan 9
  17. #define tisic 47
  18. #define soclose 1e-9
  19. #define pi 3.1415926535898
  20. #define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
  21. #define chocolate win
  22. #define ff first
  23. #define ss second
  24. #define abs(x) ((x < 0)?-(x):(x))
  25. #define uint unsigned int
  26. // mylittlepony
  27. using namespace std;
  28.  
  29. int N,M;
  30. vector< vector< pair<int,int> > > G;
  31.  
  32. bool bipar(int k) { // len prvych k (< k)
  33. 	vector<int> part(N,-1);
  34. 	queue<int> q;
  35. 	for(int i =0; i < N; i++) if(part[i] == -1) {
  36. 		q.push(i);
  37. 		part[i] =0;
  38. 		while(!q.empty()) {
  39. 			int a =q.front();
  40. 			ALL_THE(G[a],it) if(it->ss < k && part[it->ff] == -1) {
  41. 				part[it->ff] =1-part[a];
  42. 				q.push(it->ff);}
  43. 			q.pop();}
  44. 		}
  45. 	for(int i =0; i < N; i++) ALL_THE(G[i],it)
  46. 		if(part[i] == part[it->ff] && it->ss < k) return false;
  47. 	return true;}
  48.  
  49. int main() {
  50. 	cin.sync_with_stdio(0);
  51. 	cin >> N >> M;
  52. 	G.resize(N);
  53. 	for(int i =0; i < M; i++) {
  54. 		int a,b;
  55. 		cin >> a >> b;
  56. 		G[--a].push_back(make_pair(--b,i));
  57. 		G[b].push_back(make_pair(a,i));}
  58.  
  59. 	int a =0, b =M;
  60. 	while(b-a > 1) {
  61. 		int c =(b+a)/2;
  62. 		if(bipar(c)) a =c;
  63. 		else b =c;}
  64. 	cout << b << "\n";
  65. 	return 0;}
  66.  
  67. // look at my code
  68. // my code is amazing
  69.  
Success #stdin #stdout 0s 3436KB
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https://ideone.com/wcbbCN
coci sumo
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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