标签：最小生成树

继续畅通工程

3
1 2 1 0
1 3 2 0
2 3 4 0
3
1 2 1 0
1 3 2 0
2 3 4 1
3
1 2 1 0
1 3 2 1
2 3 4 1
0

3
1
0

#include <stdio.h>
#include <string.h>
#define M 105
#define INF 0x3f3f3f3f

int map[M][M], low[M], n;
bool vis[M];

int prim(){
    int i, min, pos = 1, j;
    for(i = 1; i <= n; i ++){
        low[i] = map[pos][i];
        vis[i] = 0;
    } 
    int ans = 0;
    vis[pos] = 1;
    for(i = 1; i < n; i++){
        min=  INF;
        for(j = 1; j <= n; j ++){
            if(!vis[j]&&low[j] < min){
                min = low[j]; pos = j;
            }
        }
        if(min == INF) break;
        vis[pos] = 1;
        ans += min;
        for(j = 0; j <= n; j ++)
            if(!vis[j]&&map[pos][j] < low[j])
                low[j] = map[pos][j];
    }
    return ans;
}

int main(){
    while(scanf("%d", &n), n){
        int i, a, b, c, d, j;
        for(i = 1; i <= n; i ++)
        for(j = 1; j <= n; j ++)
        map[i][j] = INF;
        for(i = 0; i < n*(n-1)/2; i++){
            scanf("%d%d%d%d", &a, &b, &c, &d);
            if(d){
                map[a][b] = map[b][a] = 0; continue;
            }
            if(map[a][b] > c)
                map[a][b] = map[b][a] = c;
        }
        printf("%d\n", prim());
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
#include <algorithm>
#define M 105
#define INF 0x3f3f3f3f
using namespace std;

struct node{
    int from, to, val;
}s[M*M];
int fat[M], tot, n;

int f(int x){
    if(fat[x] != x) fat[x] = f(fat[x]);
    else return x;
}

int cmp(node a, node b){
    return a.val<b.val;
}

int kruskal(){
    int i;
    for(i = 1; i <= n; i ++) fat[i] = i;
    int ans = 0;
    sort(s, s+tot, cmp);
    for(i = 0; i< tot; i ++){
        //printf("%d%d%d..\n", s[i].from, s[i].to, s[i].val);
        int x = f(s[i].from);
        int y = f(s[i].to);
        //printf("%d..%d..\n", x, y);
        if(x != y){
            ans += s[i].val;
            fat[y] = x;
        }
    }
    return ans;
}

int main(){
    while(scanf("%d", &n), n){
        tot = n*(n-1)/2;
        int i, a, b, c, d;
        for(i = 0; i < tot; i++){
            scanf("%d%d%d%d", &s[i].from, &s[i].to, &s[i].val, &d);
            if(d) s[i].val = 0;
        }
        printf("%d\n", kruskal());
        
    }
    return 0;
}

hdoj 1879 继续畅通工程 【最小生成树】

标签：最小生成树

原文地址：http://blog.csdn.net/shengweisong/article/details/41014235