Perimeter of the triangle and (violence)

 

 Topic ensure the three points are not collinear, that can be any three points form a triangle

I did not know how to think, but also think of the judgment is not a triangle, it may be a question of reason, usually I do not think this question is no hope

Suppose there are five points ABCDE

You can have a triangular configuration

ABC ABD ABE

ACD    ACE

ADE

BCD BCE 

BDE

CDE

All triangular perimeter and 

Into each side

For example, AB appeared three times in all triangles

AC is three times

The other side is three times

 

If there are n number of times each edge appears that n - 2 times

#include <bits/stdc++.h>

using namespace std;
#define int long long
const int maxn = 1e3 + 5;
const int mod = 998244353;
int n;
int ans;
pair<int,int> p[maxn];

int dist(pair<int,int> a,pair<int,int> b){
    return abs(a.first - b.first) + abs(a.second - b.second);
}
signed main() {
    //freopen("in", "r", stdin);
    ios::sync_with_stdio();
    cin >> n;

    for (int i = 1; i <= n; i++)
        cin >> p[i].first >> p[i].second;

    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n; j++)
            ans = (ans + dist(p[i],p[j]) * (n - 2)) % mod;
    }

    cout << ans;
    return 0;
}