# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
349635 | 2021-01-18T05:08:24 Z | my99n | Star triangles (IZhO11_triangle) | C++17 | 0 ms | 0 KB |
#include<bits/stdc++.h> using namespace std; int x[300100], y[300100]; map<int,long long> mx, my; int main(){ ios_base::sync_with_stdio(false); cin.tie(NULL); int n; cin >> n; for (int i = 0; i < n; i++) { cin >> x[i] >> y[i]; mx[x[i]++; my[y[i]]++; } long long ans; for (int i = 0; i < n; i++) ans+=(mx[x[i]]-1)*(my[y[i]]-1) cout << ans; return 0; }