Add 18868.cpp

Author: Hiyabye

18xxx/18868.cpp

@@ -0,0 +1,36 @@
+#include <algorithm>
+#include <iostream>
+#include <vector>
+using namespace std;
+
+bool check(int n, const vector<pair<int, int>> &a, const vector<pair<int, int>> &b) {
+  for (int i=0; i<n; i++) {
+    if (a[i].second != b[i].second) return false;
+  }
+  return true;
+}
+
+void solve(void) {
+  int m, n; cin >> m >> n;
+  vector<vector<pair<int, int>>> v(m, vector<pair<int, int>>(n));
+  for (int i=0; i<m; i++) for (int j=0; j<n; j++) cin >> v[i][j].first, v[i][j].second = j;
+
+  for (int i=0; i<m; i++) sort(v[i].begin(), v[i].end());
+  for (int i=0; i<m; i++) for (int j=1; j<n; j++) {
+    if (v[i][j].first == v[i][j-1].first) v[i][j].second = v[i][j-1].second;
+  }
+
+  int ans = 0;
+  for (int i=0; i<m-1; i++) for (int j=i+1; j<m; j++) {
+    if (check(n, v[i], v[j])) ans++;
+  }
+  cout << ans;
+}
+
+int main(void) {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr);
+
+  solve();
+  return 0;
+}