Dijkstra算法详解-优快云博客

描述：小明到小华家有许多条路可以走，现在给出所有能够到达他家的路线，并给出每条线段的长度，求出小明到小华家的最短路线！

介绍第一种学习方法：dijkstra算法

顶点集分为两组，第一组为：已求出最短路径的顶点集合

　　　　　　　　第二组为：其余未确定最短路径的顶点集合

按照最短路径长度递增次序把第二组中的顶点依次加入到第一组中

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<climits>
#include<queue>
#include<algorithm>
using namespace std;

#define N 110
#define MAX 999999
#define CLR(arr, what) memset(arr, what, sizeof(arr))

int nodenum, edgenum; 
int map[N][N], dis[N];
bool visit[N];

int Dijkstra(int src, int des)
{
    int temp, k;
    CLR(visit, false);
	int i = 1 ;
    for(; i <= nodenum; ++i)
        dis[i] = (i == src ? 0 : map[src][i]);
    visit[src] = true;
    dis[src] = 0;
    for(i = 1; i<= nodenum; ++i)
    {
        temp = MAX;
		int j = 1 ;
        for(; j <= nodenum; ++j)
            if(!visit[j] && temp > dis[j])
                temp = dis[k = j];
        if(temp == MAX)
            break;
        visit[k] = true;
        for(j = 1; j <= nodenum; ++j)
            if(!visit[j] && dis[j] > dis[k] + map[k][j])
                dis[j] = dis[k] + map[k][j];
    }
    return dis[des];
}

int main()
{
    int start, end, cost;
    int answer;
    while(~scanf("%d%d", &nodenum, &edgenum) && (nodenum + edgenum))
    {
		int i = 1 ;
        for(; i <= nodenum; ++i)
            for(int j = 1; j <= nodenum; ++j)
            map[i][j] = MAX;
        for(i = 1; i <= edgenum; ++i)
        {
            scanf("%d%d%d", &start, &end, &cost);
            if(cost < map[start][end])
                map[start][end] = map[end][start] = cost;
        }
        answer = Dijkstra(1, nodenum);
        printf("%d\n", answer);
    }
    return 0;
}

转载于:https://www.cnblogs.com/NYNU-ACM/p/4237463.html