Eddy’s picture
裸的最小生成树
#include<bits/stdc++.h>
using namespace std;
double x[105];
double y[105];
int root[105];
int sum = 0;
double minTree = 0.0;
struct node {
int i;
int j;
double len;
}edge[10005];
int f(int x) {
if(x == root[x]) return x;
return (root[x] = f(root[x]));
}
bool cmp(node a, node b) {
return a.len < b.len;
}
void krusual() {
for(int i = 1; i <= sum; i++) {
if(f(edge[i].i) != f(edge[i].j)) {
minTree += edge[i].len;
root[edge[i].j] = edge[i].j;
}
}
}
int main() {
int n;
while(cin >> n) {
for(int i = 1; i <= n; i++) {
root[i] = i;
}
sum = 0;
minTree = 0.0;
for(int i = 1; i <= n; i++) {
cin >> x[i] >> y[i];
for(int j = 1; j <= i; j++) {
edge[++sum].i = i;
edge[sum].j = j;
edge[sum].len = sqrt((x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]));
}
}
sort(edge + 1, edge + 1 + sum, cmp);
krusual();
printf("%.2f\n", minTree);
}
return 0;
}