洛谷 #1550. 打井
阿新 • • 發佈:2018-11-24
題意
在一個點打井cost[i],連線兩個點dis[i][j],求使所有點間接或直接與水井連通的最小花費
題解
對於在一個點打井,視為與0節點連一條邊,然後krusual即可
除錯記錄
無
#include <cstdio>
#include <algorithm>
#define maxn 305
using namespace std;
struct node{
int u, v, l;
}e[maxn * maxn << 2];
int tot = 0;
void addedge(int u, int v, int l) {e[++tot] = (node){u, v, l};}
bool cmp(const node &a, const node &b){return a.l < b.l;}
int n, f[maxn];
int getf(int x){return (f[x] == x) ? x : f[x] = getf(f[x]);}
int Krusual(){
sort(e + 1, e + tot + 1, cmp);
for (int i = 1; i <= n; i++) f[i] = i;
int res = 0;
for (int i = 1; i <= tot; i++){
if (getf(e[i].u) != getf(e[i].v)){
f[getf(e[i].u)] = getf(e[i].v);
res += e[i].l;
}
}
return res;
}
int main(){
scanf("%d", &n);
for (int x, i = 1; i <= n; i++){
scanf("%d", &x);
addedge(0, i, x);
}
for (int x, i = 1; i <= n; i++)
for (int j = 1; j <= n; j++){
scanf("%d", &x);
addedge(i, j, x);
}
printf("%d\n", Krusual());
return 0;
}