最小生成树 最短路

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int prime(int cur)
{
    int index;
    int sum = 0;
    memset(visit, false, sizeof(visit));
    visit[cur] = true;
    for(int i = 0; i < m; i ++){
        dist[i] = graph[cur][i];    
    }
    
    for(int i = 1; i < m; i ++){
        
        int mincost = INF;
        for(int j = 0; j < m; j ++){
            if(!visit[j] && dist[j] < mincost){
                mincost = dist[j];
                index = j;    
            }    
        }
        
        visit[index] = true;
        sum += mincost;
        
        for(int j = 0; j < m; j ++){
            if(!visit[j] && dist[j] > graph[index][j]){
                dist[j] = graph[index][j];
            }    
        }    
    } 
    return sum;    
}

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#include<iostream>
#include<algorithm>
using namespace std;

const int size = 128; 
int n;
int father[size];
int rank[size];

//把每条边成为一个结构体，包括起点、终点和权值 
typedef struct node
{
    int val;
    int start;
    int end;    
}edge[SIZE * SIZE / 2];

//把每个元素初始化为一个集合 
void make_set()
{
    for(int i = 0; i < n; i ++){
        father[i] = i;
        rank[i] = 1;    
    }    
    return ;
}

//查找一个元素所在的集合,即找到祖先 
int find_set(int x)
{
    if(x != father[x]){
        father[x] = find_set(father[x]);    
    }    
    return father[x];
}

//合并x,y所在的两个集合：利用Find_Set找到其中两个
//集合的祖先，将一个集合的祖先指向另一个集合的祖先。
void Union(int x, int y)
{
    x = find_set(x);    
    y = find_set(y);
    if(x == y){
        return ;    
    }
    if(rank[x] < rank[y]){
        father[x] = find_set(y);    
    }
    else{
        if(rank[x] == rank[y]){
            rank[x] ++;    
        }    
        father[y] = find_set(x);
    }
    return ;
}

bool cmp(pnode a, pnode b)
{
    return a.val < b.val;    
}

int kruskal(int n) //n为边的数量 
{
    int sum = 0;
    make_set();
    for(int i = 0; i < n; i ++){   //从权最小的边开始加进图中 
        if(find_set(edge[i].start) != find_set(edge[i].end)){
            Union(edge[i].start, edge[i].end);
            sum += edge[i].val;    
        }    
    }
    return sum;    
}

int main()
{
    while(1){
        scanf("%d", &n);    
        if(n == 0){
            break;    
        }
        char x, y;
        int m, weight;
        int cnt = 0;
        for(int i = 0; i < n - 1; i ++){
            cin >> x >> m; 
            //scanf("%c %d", &x, &m);    
            //printf("%c %d ", x, m);
            for(int j = 0; j < m; j ++){
                cin >> y >> weight; 
                //scanf("%c %d", &y, &weight);
                //printf("%c %d ", y, weight);    
                edge[cnt].start = x - 'A';
                edge[cnt].end = y - 'A';
                edge[cnt].val = weight;
                cnt ++;
            }
        }
        
        sort(edge, edge + cnt, cmp); //对边按权从小到大排序 
        cout << kruskal(cnt) << endl; 
    }    
}

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void floyd()
{
    for(int k = 0; k < n; k ++){ //作为循环中间点的k必须放在最外一层循环 
        for(int i = 0; i < n; i ++){
            for(int j = 0; j < n; j ++){
                if(dist[i][j] > dist[i][k] + dist[k][j]){
                    dist[i][j] = dist[i][k] + dist[k][j];    //dist[i][j]得出的是i到j的最短路径 
                }     
            }    
        }    
    }    
}

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void dijkstra(int s)   //s是起点
{
    memset(visit, false, sizeof(visit));    
visit[s] = true;
    for(int i = 0; i < n; i ++){
        dist[i] = graph[s][i];
    }
     
    int index;
    for(int i = 1; i < n; i ++){
        int mincost = INF;
        for(int j = 0; j < n; j ++){
            if(!visit[j] && dist[j] < mincost){
                mincost = dist[j];
                index = j;    
            }    
        }
        visit[index] = true;
        for(int j = 0; j < n; j ++){
            if(!visit[j] && dist[j] > dist[index] + graph[index][j]){
                dist[j] = dist[index] + graph[index][j];
            }    
        }    
    }
}