Title description
Problem
Given n points on a plane, find the diameter of the convex hull.
Input format
The first line is a positive integer n.
In the next n lines, each line contains two integers x and y, representing the coordinates of a point.
Output format
Output an integer on a line, representing the square of the answer.
Sample input and output
Enter #1
4
0 0
0 1
1 1
1 0
Output #1
2
analysis:
Approximately O (n 2) O(n^2)O ( n2 )Complexity +a bunch of metaphysical operationsLuogu has ever been on the Purple Question?
The Pythagorean Theoremviolently seeks the maximum distance to limit the operation
CODE：
#include<iostream>
#include<cstdio>
using namespace std;
typedef long long ll;
ll n,x[50005],y[50005],ans;
int main(){
scanf("%lld",&n);
if(n==1)
{
printf("-1");
return 0; //数据问题
}
n=min(48000ll,n); //玄学
for(register int i=1;i<=n;i++)
{
scanf("%lld%lld",&x[i],&y[i]);
for(register int j=1;j<i;j++)
ans=max(ans,(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j])); //勾股求距离
}
printf("%lld",ans);
return 0;
}