dfs + 链式向前星

 用链式向前星存图，用bfs求出起点到终点的最小步数

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

struct node
{
	int to,next;
	int w;
}edge[100];
int head[100];
int vis[100];
int total = 1;
void AddEdge(int u, int v, int w)
{
	edge[total].to = v;
	edge[total].w = w;
	edge[total].next = head[u];
	head[u] = total ++;
}
int Min = 9999;
int time = 0;
 
void dfs(int start, int end, int step)
{
	//cout << "start=" << start << endl;
	//cout << "end=" << end << endl; 
	
	if(start == end) 
	{
	//	cout << (++time) << " " ;
	//	cout << "step=" << step << endl;;
		if(Min > step)
		{
			Min = step;
		}
		
		return ;
	}
	
	for(int i = head[start]; i != -1; i = edge[i].next)
	{
		int to = edge[i].to;
		if(!vis[to])
		{
			vis[to] = 1;
//			int now_start = edge[i].to;
//			int now_end =  end;
//			dfs(now_start, now_end, step+1);
			
			dfs(to,end, step + 1);//（step + edge[i].w） 为计算权重，（step + 1)为计算最短步数 
			vis[to] = 0;
		}
	}
}

int main()
{
	int n,  m;
	
	cin >> n >> m;
	memset(head, -1, sizeof(head));
	memset(vis, 0, sizeof(vis));
	int u, v, w;
	for(int i = 1; i <= m; i++)
	{
		cin >> u >> v >> w;
		AddEdge(u, v, w);
	}	
	dfs(1, n, 0);
	cout << Min << endl;
	return 0;
	
} 
/*
7 10  //7个顶点，10条边，求1号顶点到7号定点的最小步数
1 2 1 //起点为1，终点为2，边权为1 
1 3 1
2 4 1
2 5 1
3 5 1
3 6 1
4 5 1
4 7 1
6 7 1
5 6 1

7 10
1 2 5
1 3 5 
2 4 1
2 5 1
3 5 1
3 6 1
4 5 1
4 7 1
5 7 1
6 7 1

*/