POJ-3411-Paid Roads

dfs,用邻接表，有重边

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
#include <cmath>
#include <stdlib.h>
using namespace std;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int MAX = 1e1+10;
const int mod = 1e9+7;
int a, b, c, p, r, n, m, ans, vis[11], top;
struct edge
{
int p, r, b, next, c;
}lxt[MAX];
int adj[MAX];
void add(int a, int b, int c, int p, int r)
{
lxt[top].b = b;
lxt[top].c = c;
lxt[top].p = p;
lxt[top].r = r;
lxt[top].next = adj[a];
adj[a] = top++;
}
void dfs(int pre, int cost)
{
if(pre==n)
{
ans = min(ans, cost);
return;
}
if(cost>=ans)return;
for(int i = adj[pre]; i!=-1; i=lxt[i].next)
{
c = lxt[i].c;
p = lxt[i].p;
r = lxt[i].r;
int b = lxt[i].b;//迷之bug，必须定义成局部，不然会wa
if(vis[b]<=3)
{
vis[b]++;
if(vis[c]>0)dfs(b,cost+p);
else dfs(b,cost+r);
vis[b]--;
}
}
}
int main()
{
cin>>n>>m;
top = 0;
ans = mod;
memset(vis, 0, sizeof(vis));
memset(adj, -1, sizeof(adj));
while(m--)
{
cin>>a>>b>>c>>p>>r;
add(a,b,c,p,r);
}
vis[1] = 1;
dfs(1, 0);
if(ans!=mod)cout<<ans<<endl;
else cout<<"impossible"<<endl;
return 0;
}