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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     ios::sync_with_stdio(false);
  6.     cin.tie(nullptr);
  7.  
  8.     int n;
  9.     cin >> n;
  10.     vector<int> P(n);
  11.     for (int i = 0; i < n; i++) cin >> P[i];
  12.  
  13.     long long inv = 0;
  14.     for (int i = 0; i < n; i++) {
  15.         for (int j = i+1; j < n; j++) {
  16.             if (P[i] > P[j]) inv++;
  17.         }
  18.     }
  19.  
  20.     long long total = 1LL * n * (n-1) / 2;
  21.  
  22.     if ((inv % 2) != (total % 2)) {
  23.         cout << 0 << "\n";
  24.         return 0;
  25.     }
  26.  
  27.     cout << 1 << "\n";
  28.     // 올바른 교환 순서: 왼쪽에서 오른쪽으로
  29.     for (int i = 1; i <= n-1; i++) {
  30.         for (int j = i+1; j <= n; j++) {
  31.             cout << i << " " << j << "\n";
  32.         }
  33.     }
  34. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/V6YSCE
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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