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  1. #include <iostream>
  2. #include <vector>
  3. #include <unordered_set>
  4. using namespace std;
  5. int t, n, x, y;
  6.  
  7. struct hashFunction {
  8.   size_t operator()(const pair<int,int> &x) const {
  9.     return x.first ^ x.second;
  10.   }
  11. };
  12.  
  13. vector<pair<int, int> > vec;
  14.  
  15. int main() {
  16.     scanf("%d", &t);
  17.     while(t--) {
  18.         vec.clear();
  19.         unordered_set<pair<int, int>, hashFunction> left;
  20.         unordered_set<pair<int, int>, hashFunction> right;
  21.         scanf("%d", &n);
  22.         int min = 10005, max = -10005;
  23.         for (int i = 0; i < n; i++) {
  24.             scanf("%d%d", &x, &y);
  25.             vec.emplace_back(make_pair(x, y));
  26.             if (x < min) min = x;
  27.             if (x > max) max = x;
  28.         }
  29.         double mid = (double)(min + max) / 2;
  30.         for (auto &it : vec) {
  31.             if (it.first < mid) left.insert(it);
  32.             else if (it.first > mid) right.insert(it);
  33.         }
  34.         if (left.size() != right.size()) printf("NO\n");
  35.         else {
  36.             bool f = true;
  37.             for (auto &it : left) {
  38.                 int rightX = (min + max) - it.first;
  39.                 pair<int, int> rightMatch = make_pair(rightX, it.second);
  40.                 if (right.find(rightMatch) == right.end()) {
  41.                     f = false;
  42.                     break;
  43.                 }
  44.             }
  45.             if (f) printf("YES\n");
  46.             else printf("NO\n");
  47.         }
  48.     }
  49.     return 0;
  50. }
Success #stdin #stdout 0.01s 5460KB
comments (?)
stdin
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3
5
-2 5
0 0
6 5
4 0
2 3
4
2 3
0 4
4 0
0 0
4
5 14
6 10
5 10
6 14
stdout
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YES
NO
YES
https://ideone.com/2gYWAj
language:
C++14 (gcc 8.3)
created:
1 year ago
visibility:
public

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