Submission #426136

#	Time	Username	Problem	Language	Result	Execution time	Memory
426136		SuckTinHock	Star triangles (IZhO11_triangle)	C++17	0 / 100	298 ms	33796 KiB

triangle

#include <bits/stdc++.h>
#define int long long
#define x first
#define y second

using namespace std;
typedef pair<int,int> Point;
Point P[300005];
int n;
int cntx[300005], cnty[300005];

void compress()
{
    vector<int> A;
    for (int i = 1; i <= n; ++i)
    {
        A.push_back(P[i].x);
        A.push_back(P[i].y);
    }
    sort(A.begin(),A.end());
    unique(A.begin(),A.end());
    for (int i = 1; i <= n; ++i)
    {
        P[i].x = lower_bound(A.begin(),A.end(),P[i].x) - A.begin();
        P[i].y = lower_bound(A.begin(),A.end(),P[i].y) - A.begin();
    }
}

void xuly()
{
    int res = 0;
    compress();
    sort(P+1,P+n+1);
    vector<pair<Point,int> > PP;
    for (int i = 1; i <= n; ++i)
    {
        PP.push_back({P[i],1});
        while (i+1 <= n && P[i] == P[i+1]) ++PP.back().y, ++i;
        cntx[P[i].x] += PP.back().y;
        cnty[P[i].y] += PP.back().y;
    }
    for (pair<Point,int> T : PP)
    {
        Point X = T.x;
        int cnt = T.y;
        res += (cntx[X.x] - cnt) * (cnty[X.y] - cnt);
    }
    cout << res;
}

void nhap()
{
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> P[i].x >> P[i].y;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    nhap();
    xuly();
    return 0;
}

• Subtask 1: 0 / 100