戳我传送 A、最短路 思路: Code: #include<bits/stdc++.h> #define js ios::sync_with_stdio(false);cin.tie(0);cout.tie(0) #define dis(a,b,c,d) sqrt((a-c)*(a-c)+(b-d)*(b-d)) #define ll long long using namespace std; int main() { js; double x1,y1,x2,y2,x3,y3,r; cin>>x1>>y1>>x2>>y2...