URAL 1031. Railway Tickets(spfa)

题目链接

不知为何会在dp里呢。。。INF取小了，2Y。

#include <cstring>
#include <cstdio>
#include <string>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <cmath>
using namespace std;
#define INF 1e9
int l1,l2,l3,c1,c2,c3;
int p[20001];
int dis[20001];
int in[20001];
int judge(int x,int y)
{
    int d = p[x] - p[y];
    if(d < 0)
    d = -d;
    if(d <= l1)
    return c1;
    if(d <= l2)
    return c2;
    if(d <= l3)
    return c3;
    return INF;
}
int main()
{
    int i,n,sv,ev,w,u;
    queue<int>que;
    scanf("%d%d%d%d%d%d",&l1,&l2,&l3,&c1,&c2,&c3);
    scanf("%d",&n);
    scanf("%d%d",&sv,&ev);
    for(i = 2;i <= n;i ++)
    scanf("%d",&p[i]);
    for(i = 1;i <= n;i ++)
    {
        dis[i] = INF;
        in[i] = 0;
    }
    dis[sv] = 0;
    in[sv] = 1;
    que.push(sv);
    while(!que.empty())
    {
        u = que.front();
        que.pop();
        in[u] = 0;
        for(i = 1;i <= n;i ++)
        {
            w = judge(i,u);
            if(dis[i] > dis[u] + w)
            {
                dis[i] = dis[u] + w;
                if(!in[i])
                {
                    in[i] = 1;
                    que.push(i);
                }
            }
        }
    }
    printf("%d
",dis[ev]);
    return 0;
}