3 files changed, 84 insertions, 0 deletions
diff --git a/contests/Round939/B/main.cpp b/contests/Round939/B/main.cpp
new file mode 100755
index 0000000..ae6b84c
--- /dev/null
+++ b/contests/Round939/B/main.cpp
@@ -0,0 +1,68 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpii = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x)                                                         \
+  sort(all((x)));                                                              \
+  (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b)-1) / (b)
+
+const int mod = (int)1e9 + 7;
+const db pi = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+#ifdef LOCAL
+#include "debug.h"
+#else
+#define dbg(...) 42
+#endif
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+void solve() {
+  int n;
+  cin >> n;
+  vi v(n);
+  mpii fq;
+  int ans = 0;
+  for (auto &x : v) {
+    cin >> x;
+    fq[x]++;
+    if (fq[x] == 2) {
+      ans++;
+    }
+  }
+  cout << ans << '\n';
+}
+
+int main() {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while (tt--) {
+    solve();
+  }
+}
diff --git a/contests/Round939/B/main_input0.txt b/contests/Round939/B/main_input0.txt
new file mode 100644
index 0000000..b508434
--- /dev/null
+++ b/contests/Round939/B/main_input0.txt
@@ -0,0 +1,11 @@
+5
+4
+1 1 2 3
+8
+7 4 1 2 8 8 5 5
+8
+7 1 4 5 3 4 2 6
+3
+1 2 3
+1
+1
diff --git a/contests/Round939/B/main_output0.txt b/contests/Round939/B/main_output0.txt
new file mode 100644
index 0000000..9a33115
--- /dev/null
+++ b/contests/Round939/B/main_output0.txt
@@ -0,0 +1,5 @@
+1
+2
+1
+0
+0