最优灌溉

#include <iostream>
using namespace std;
const int MAXCOST = 99999;
bool prime(int **matrix, int n,int& count,int& lowcost)
{
    int *flag = new int[n + 1];
    int index;
    int curlowCost = MAXCOST;
    int *cost = new int[n + 1];
    for (int i = 0; i <= n; i++)
    {
        cost[i] = MAXCOST;
    }

    //初始化
    flag[1] = 1;
    for (int i = 2; i <= n; i++)
    {
        cost[i] = matrix[1][i];
        flag[i] = 0;
    }

    for (int j = 2; j <= n; j++)
    {
        curlowCost = MAXCOST;
        for (int i = 1; i <= n; i++)
        {
            if (cost[i] < curlowCost && flag[i] == 0)
            {
                curlowCost = cost[i];
                index = i;
            }
        }

        flag[index] = 1;
        lowcost += curlowCost;
        for (int k = 1; k <= n; k++)
        {
            if (flag[k] == 0 && matrix[index][k] < cost[k])
                cost[k] = matrix[index][k];
        }
    }
    

    for (int i = 1; i <= n; i++)
    {
        if (flag[i] == 1)
            count++;
    }
    delete[] flag;

    if (count == n)
        return true;
    else
        return false;

}

void main(void)
{
    int m, n;
    int row, col, val;
    while (cin >> n>>m){
        int count = 0, lowcost = 0;
        int **matrix;
        matrix = new int*[n+1];
        for (int i = 0; i <= n; i++)
        {
            matrix[i] = new int[n+1];
        }

        for (int i = 0; i <= n;i++)
            for (int j = 0; j <= n; j++)
            {
                matrix[i][j] = MAXCOST;
            }

        for (int i = 1; i <= m; i++)
        {
            cin >> row >> col >> val;
            matrix[row][col] = matrix[col][row] = val;
        }

        if (prime(matrix, n, count, lowcost))
            cout << lowcost << endl;
        else
            cout << "error";

        for (int i = 0; i <= n; i++)
            delete[] matrix[i];

    }

}