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  1. #include <iostream>
  2. #include <vector>
  3. #include <algorithm>
  4.  
  5. using namespace std;
  6.  
  7. struct Rectangle {
  8.     int h, w, index;
  9. };
  10.  
  11. // Compare function for sorting
  12. bool compare(const Rectangle &a, const Rectangle &b) {
  13.     if (a.h == b.h) return a.w < b.w;
  14.     return a.h < b.h;
  15. }
  16.  
  17. int main() {
  18.     int n;
  19.     cin >> n;
  20.  
  21.     vector<Rectangle> rects(n);
  22.  
  23.     for (int i = 0; i < n; i++) {
  24.         int h, w;
  25.         cin >> h >> w;
  26.         if (h > w) swap(h, w); // Ensure h ≤ w
  27.         rects[i] = {h, w, i + 1}; // Store original index
  28.     }
  29.  
  30.     // Sort rectangles
  31.     sort(rects.begin(), rects.end(), compare);
  32.  
  33.     // LIS on widths
  34.     vector<int> dp(n, 1), prev(n, -1);
  35.     int max_len = 1, last_index = 0;
  36.  
  37.     for (int i = 0; i < n; i++) {
  38.         for (int j = 0; j < i; j++) {
  39.             if (rects[j].w < rects[i].w) { // Only compare widths
  40.                 if (dp[j] + 1 > dp[i]) {
  41.                     dp[i] = dp[j] + 1;
  42.                     prev[i] = j;
  43.                 }
  44.             }
  45.         }
  46.         if (dp[i] > max_len) {
  47.             max_len = dp[i];
  48.             last_index = i;
  49.         }
  50.     }
  51.  
  52.     // Retrieve the sequence
  53.     vector<int> sequence;
  54.     for (int i = last_index; i != -1; i = prev[i]) {
  55.         sequence.push_back(rects[i].index);
  56.     }
  57.  
  58.     reverse(sequence.begin(), sequence.end());
  59.  
  60.     // Output results
  61.     cout << max_len << endl;
  62.     for (int i : sequence) cout << i << " ";
  63.     cout << endl;
  64.  
  65.     return 0;
  66. }
Success #stdin #stdout 0.02s 5288KB
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https://ideone.com/rFolub
language:
C++14 (gcc 8.3)
created:
9 days ago
visibility:
public

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