Prim算法模板

//Gang
#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#define FOR(x,y,z) for(int x=y;x<=z;x++)
#define REP(x,y,z) for(int x=y;x>=z;x--)
#define ll long long
using namespace std;
][];  //邻接矩阵
];     //标记数组
];     //边的权值
];         //记录生成树的路径
int source;            //指定生成树的起点
int vertex_num;        //顶点数
int arc_num;           //弧数
int sum;               //生成树权和

void Prim(int source)
{
    memset(visited, , sizeof(visited));
    visited[source] = true;
    ; i < vertex_num; i++)
    {
        low_cost[i] = matrix[source][i];
        path[i] = source;
    }

    int min_cost;        //权值最小
    int min_cost_index;  //权值最小的下标
    sum = ;
    ; i < vertex_num; i++)  //除去起点，还需要找到另外vertex_num-1个点
    {
        min_cost = INT_MAX;
        ; j < vertex_num; j++)
        {
            if (visited[j] == false && low_cost[j] < min_cost)  //找到权值最小
            {
                min_cost = low_cost[j];
                min_cost_index = j;
            }
        }

        visited[min_cost_index] = true;   //该点已找到，进行标记
        sum += low_cost[min_cost_index];  //更新生成树权和

        ; j < vertex_num; j++)  //从找到的最小下标更新low_cost数组
        {
            if (visited[j] == false && matrix[min_cost_index][j] < low_cost[j])
            {
                low_cost[j] = matrix[min_cost_index][j];
                path[j] = min_cost_index;
            }
        }
    }
}

int main()
{
    cin >> vertex_num;
    cin >> arc_num;
    ; i < vertex_num; i++)
        ; j < vertex_num; j++)
            matrix[i][j] = INT_MAX;  //初始化matrix数组
    int u, v, w;
    ; i < arc_num; i++)
    {
        cin >> u >> v >> w;
        matrix[u][v] = matrix[v][u] = w;
    }

    cout  << vertex_num;
    cin >> source;
    Prim(source);
    cout << sum << endl;
    ; i < vertex_num; i++)
        if (i != source)
            cout << i << "----" << path[i] << endl;

    ;
}