C - 3SUM Closure

https://codeforces.com/contest/1698/submission/162104497

Codeforces/1698/C/C.cpp

@@ -0,0 +1,73 @@
+#include <iostream>
+#include <algorithm>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+int t, n, a[N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> t;
+
+    while (t--) {
+        bool flag = true;
+        std::vector<long long> nums;
+        int cnt1 = 0, cnt2 = 0, cnt3 = 0;
+
+        cin >> n;
+
+        for (int i = 1, x; i <= n; i++) {
+            cin >> a[i];
+
+            if (a[i] < 0) cnt1++;
+            else if (a[i] > 0) cnt2++;
+            else cnt3++;
+        }
+
+        if (cnt1 > 2 || cnt2 > 2) {
+            cout << "No" << endl;
+
+            continue;
+        }
+
+        cnt3 = std::min(cnt3, 2);
+
+        for (int i = 1; i <= n; i++) {
+            if (a[i]) {
+                nums.push_back(a[i]);
+            }
+        }
+
+        for (int i = 1; i <= cnt3; i++) {
+            nums.push_back(0);
+        }
+
+        int q = nums.size();
+        for (int i = 0; i < q; i++) {
+            for (int j = i + 1; j < q; j++) {
+                for (int k = j + 1; k < q; k++) {
+                    long long x = nums[i] + nums[j] + nums[k];
+                    bool f = false;
+                    for (int l = 0; l < q; l++) {
+                        if (x == nums[l]) {
+                            f = true;
+                            break;
+                        }
+                    }
+                    if (!f) flag = false;
+                }
+            }
+        }
+
+        cout << (flag ? "Yes" : "No") << endl;
+    }
+
+    return 0;
+}