DS实验题 Floyd最短路径 & Prim最小生成树

题目：

提示：

Floyd最短路径算法实现(未测试)：

//
//  main.cpp
//  Alg_Floyd_playgame
//
//  Created by wasdns on 16/11/19.
//  Copyright ? 2016年 wasdns. All rights reserved.
//  

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <string>
#include <string.h>
using namespace std;  

#define endless 1000000001;  

int Floydgh[5005][5005];  

void Inigh(int n)
{
    for (int i = 1; i <= n; i++)
    {
        Floydgh[i][i] = 0;  

        for (int j = 1; j <= n; j++)
        {
            if (i != j) {
                Floydgh[i][j] = endless;
            }
        }
    }
}  

void Creatgh(int n, int m)
{
    Inigh(n);  

    int i, u, v, w;  

    for (i = 1; i <= m; i++)
    {
        cin >> u >> v >> w;  

        Floydgh[u][v] = w;
        Floydgh[v][u] = w;
    }
}  

void Alg_Floyd(int n)
{
    int i, j, k;  

    for (k = 1; k <= n; k++)
    {
        for (i = 1; i <= n; i++)
        {
            for (j = 1; j <= n; j++)
            {
                int t = Floydgh[i][k] + Floydgh[k][j];  

                if (t < Floydgh[i][j]) {
                    Floydgh[i][j] = t;
                    Floydgh[j][i] = t;
                }
            }
        }
    }
}  

int minjudge(int n)
{
    int i, j;  

    int minlen = endless;  

    for (i = 1; i <= n; i++)
    {
        int cnt = 0;  

        for (j = 1; j <= n; j++)
        {
            cnt += Floydgh[i][j];
        }  

        if (cnt < minlen) {
            minlen = cnt;
        }
    }  

    return minlen;
}  

int main()
{
    int n, m;  

    cin >> n >> m;  

    Creatgh(n, m);  

    Alg_Floyd(n);  

    cout << minjudge(n) << endl;  

    return 0;
} 

Prim生成树算法实现：

关于Prim算法，请参考我的另外一篇博客：hdoj-1233-还是畅通工程

//
//  main.cpp
//  Prim
//
//  Created by wasdns on 16/11/24.
//  Copyright © 2016年 wasdns. All rights reserved.
//

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <string.h>
#define maxn 10000005;
using namespace std;

int Primgh[10000][10000];

bool refer[10005];

void Initial(int n, int m)
{
    int i, j;

    for (i = 1; i <= n; i++)
    {
        refer[i] = false;

        for (j = 1; j <= n; j++)
        {
            if (i == j) {
                Primgh[i][j] = 0;
            }

            else Primgh[i][j] = maxn;
        }
    }

    int u, v, w;

    for (i = 1; i <= m; i++)
    {
        cin >> u >> v >> w;

        Primgh[u][v] = w;
        Primgh[v][u] = w;
    }
}

int Prim_Alg(int n, int m)
{
    Initial(n, m);

    int i, j, k;

    int ans = 0;

    refer[1] = true;                    //起点为1

    for (i = 1; i <= n-1; i++)
    {
        int minlen = maxn;

        int rcd = 1;

        for (j = 1; j <= n; j++)
        {
            if (!refer[j]) continue;

            int len1 = maxn;
            int rcd1 = 1;

            for (k = 1; k <= n; k++)
            {
                if (!refer[k])
                {
                    if (Primgh[j][k] < len1) {

                        len1 = Primgh[j][k];

                        rcd1 = k;
                    }
                }
            }

            if (len1 < minlen) {

                minlen = len1;

                rcd = rcd1;
            }
        }

        //char check = 'A'+rcd-1;
        //cout << "rcd: " << check << endl;
        //cout << "minlen: " << minlen << endl;

        refer[rcd] = true;
        rcd = 1;

        ans += minlen;
    }

    return ans;
}

int main()
{
    int n, m;

    cin >> n >> m;

    cout << Prim_Alg(n, m) << endl;

    return 0;
}

测试样例：

/*
 eg1. 

 Input:
 4 6
 1 2 1
 2 3 2
 1 3 3
 2 4 3
 3 4 5
 1 4 4

 Output:
 6

 eg2.

 Input:
 7 11
 1 2 7
 1 4 5
 2 4 9
 2 3 8
 2 5 7
 3 5 5
 4 5 15
 4 6 6
 5 6 8
 5 7 9
 6 7 11

 Output:
 39
 */

2016/11/24