initial commit

codeforces/991/b.cc

@@ -0,0 +1,54 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define all(x) (x).begin(), (x).end()
+#define sz(x) static_cast<int>((x).size())
+#define FOR(x) for (size_t i = 0; i < (x).size(); ++i)
+#define FORI(x) for (size_t i = 0; i < (x); ++i)
+
+#ifdef LOCAL
+#define dbg(x) cerr << #x << " = " << (x) << '\n'
+#else
+#define dbg(x)
+#endif
+
+void solve() {
+  int n;
+  cin >> n;
+  vector<int> a(n);
+
+  int total = 0;
+  FOR(a) {
+    int x;
+    cin >> x;
+    a[i] = x;
+    total += x;
+  }
+
+  long long odds = 0, evens = 0;
+  for (int i = 0; i < n; i++) {
+    (i & 1 ? odds : evens) += a[i];
+  }
+  int odd_count = n >> 1, even_count = (n >> 1) + (n & 1);
+
+  if (odds % odd_count == 0 && evens % even_count == 0 &&
+      odds / odd_count == evens / even_count) {
+    cout << "YES\n";
+  } else {
+    cout << "NO\n";
+  }
+}
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr);
+
+  int t;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}