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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5.  
  6.  
  7. const int M = 1000000007;
  8. const int N = 3e5+9;
  9. const int INF = 2e9+1;
  10. const int MAXN = 100000;
  11. const int LINF = 2000000000000000001;
  12.  
  13. //_ ***************************** START Below *******************************
  14.  
  15.  
  16.  
  17. vector<int> a;
  18.  
  19. vector<int> consistency(int n, int k){
  20.  
  21. 	vector<pair<int,int>> p(n);
  22. 	for(int i=0; i<n; i++){
  23. 		p[i] = {a[i], i};
  24. 	}
  25.  
  26. 	sort(begin(p), end(p));
  27.  
  28. 	for(int i=0; i<n-2; i++){
  29. 		int t = k-p[i].first;
  30. 		int s = i+1, e = n-1;
  31.  
  32. 		while(s<e){
  33. 			int left = p[s].first;
  34. 			int right = p[e].first;
  35.  
  36.  
  37. 			if(left + right == t) {
  38. 				vector<int> ans = {p[i].second+1, p[s].second+1, p[e].second+1};
  39. 				sort(begin(ans), end(ans));
  40. 				return ans;
  41. 			}
  42. 			else if(left + right > t){
  43. 				e--;
  44. 			}
  45. 			else {
  46. 				s++;
  47. 			}
  48. 		}
  49. 	}
  50.  
  51. 	return {};
  52. }
  53.  
  54.  
  55.  
  56.  
  57.  
  58.  
  59.  
  60.  
  61.  
  62. vector<int> practice(int n, int k){
  63.  
  64. 	return {};
  65. }
  66.  
  67.  
  68.  
  69.  
  70. void solve() {
  71.  
  72. 	int n, k;
  73. 	cin >> n >> k;
  74.  
  75. 	a.resize(n);
  76. 	for(int i=0; i<n; i++) cin >> a[i];
  77.  
  78.  
  79. 	auto ans1 = consistency(n, k);
  80. 	if(ans1.empty()) cout << "IMPOSSIBLE" << endl;
  81. 	else cout << ans1[0] << " " << ans1[1] << " " << ans1[2] << endl;
  82.  
  83.  
  84. 	// auto p = practice(n, k);
  85. 	// if(p.empty()) cout << " -> " << "IMPOSSIBLE" << endl;
  86. 	// else cout << " -> " << ans1[0] << " " << ans1[1] << " " << ans1[2] << endl;
  87.  
  88. }
  89.  
  90.  
  91.  
  92.  
  93.  
  94. int32_t main() {
  95.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  96.  
  97.     int t = 1;
  98.     while (t--) {
  99.         solve();
  100.     }
  101.  
  102.     return 0;
  103. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/88gyVt
language:
C++14 (gcc 8.3)
created:
4 hours ago
visibility:
public

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