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该点到三角形三个顶点距离相同，即三角形的外心。#include<bits/stdc++.h>using namespace std;int main(){ double x1, x2, x3, y1, y2, y3; cin>>x1>>y1>>x2>>y2>>x3>>y3; double A1 = 2 * (x2 - x1), B1 = 2 * (y2 - y1), C1 =

#include<bits/stdc++.h>using namespace std;const int N=1e5*2+10;int h[N],e[N],ne[N],idx,st[N];int n,ans=1e9;void add(int a,int b){ e[idx]=b,ne[idx]=h[a],h[a]=idx++;}int dfs(int u){ int sum=0,maxv=0; st[u]=1; for(int i=h[u];i!

#include<bits/stdc++.h>using namespace std;unordered_map<char,int>pr{{'+',1},{'-',1},{'*',2},{'/',2}};string s;stack<char>op;stack<int>num;void eval(){ auto b=num.top(); num.pop(); auto a=num.top(); num.pop(); ch.

常见的求解方法：用归并排序计算用树状数组计算归并排序计算逆序对的数量#include<bits/stdc++.h>using namespace std;typedef long long int LL;const int N=1e5+10;LL a[N],b[N],n,ans;void merge_sort(int l,int r){ if(l>=r) return; int mid=l+r>>1; merge_sort(l,m