Create 2018-G-A.cpp

Author: tmp-coder

kick-start/2018-G-A.cpp

@@ -0,0 +1,52 @@
+#include<bits/stdc++.h>
+using namespace std;
+ 
+const int MAXN = 2e5+10;
+typedef long long LL;
+void solve(){
+    int n;
+    cin >> n;
+
+    vector<LL> num(n,0);
+    for(int i=0; i<n ; ++i)
+    {
+        cin >> num[i];
+    }
+    sort(num.begin(),num.end());
+    LL ans =0;
+    LL zeros =0;
+    for(int i=0 ; i<n ; ++i){
+        if(!num[i])
+        {
+            zeros++;
+            continue;
+        }
+        for(int j=i+1 ; j<n;++j){
+            LL k = num[i] * num[j];
+            ans+= upper_bound(num.begin()+j+1,num.end(),k) - lower_bound(num.begin()+j+1,num.end(),k);
+            
+        }
+    }
+    ans += (zeros -1) * zeros /2 * (n - zeros);
+    ans += (zeros -1) * zeros * (zeros -2)/6;
+    cout << ans << '\n';
+}
+
+int main(){
+    ios :: sync_with_stdio(0);
+    cin.tie(0);
+    // cout.tie(0);
+    std::cout.precision(10);
+    std::cout.setf( std::ios::fixed, std:: ios::floatfield );
+ 
+    int T;
+    cin >> T;
+    for(int tt =1 ; tt <=T ; ++tt)
+    {
+        cout << "Case #" << tt << ": ";
+        solve();
+    }
+    
+ 
+    return 0;
+}