图论起步（长期更新）

简单深度搜索求最短路径

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std ;

int mp[100][100] ;
int book[100000] ;
const int inf = 1e9 ;
int minStep ;
int n, m ;

void dfs(int cur,int step)
{
    if(step>minStep)
        return ;
    if(cur == n)
    {
        if(step<minStep)
            minStep = step ;
        return ;
    }
    for(int i = 1 ;i<=n ;i++)
    {
        if(mp[cur][i]!=inf && book[i] == 0)
        {
            book[i] = 1 ;
            dfs(i,step+mp[cur][i]) ;
            book[i] = 0 ;
        }
    }
}

int main()
{
    int a,b,c ;
    scanf("%d%d",&n,&m) ;
    for(int i = 1 ;i<=n ;i++)
        for(int j = 1 ; j<=n ;j++)
    {
        if(i == j)
            mp[i][j] = 0 ;
        else mp[i][j] = inf ;
    }

    while(m--)
    {
        scanf("%d%d%d",&a,&b,&c) ;
        mp[a][b] = c ;
    }
    memset(book,0,sizeof(book)) ;
    minStep = inf-10 ;
    book[1] = 1 ;
    dfs(1,0) ;
    printf("最短路径为%d
",minStep) ;
    return 0 ;
}

/*测试样例(输出为9)

5 8
1 2 2
1 5 10
2 3 3
2 5 7
3 1 4
3 4 4
4 5 5
5 3 3