ABC359B Couples

atcoder/abc359b_couples.cpp

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+// Vicfred
+// https://atcoder.jp/contests/abc359/tasks/abc359_b
+// brute force, implementation
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+int main() {
+  int N;
+  cin >> N;
+  vector<int> A(2 * N);
+  for (int i = 0; i < 2 * N; ++i) {
+    cin >> A[i];
+  }
+  int answer = 0;
+  for(int i = 1; i <= N; ++i) {
+    for(int idx = 0; idx < 2 * N; ++idx) {
+      if(A[idx] == i and A[idx + 2] == i) {
+        answer += 1;
+        break;
+      }
+    }
+  }
+  cout << answer << endl;
+  return 0;
+}