kuangbin_ShortPathE (POJ 1860)

第一次做判环 然后RE了五次 死在了奇怪的点

memset(vis, 0, sizeof dis);

memset(dis, 0, sizeof vis);

什么鬼?? 什么鬼??

其实代码本身还是不难的 就是spfa另外开个数组记录入队次数

spfa不用写cmp真是太好了 operator什么的真的搞不清

#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <queue>
#include <map>
#include <vector>
#include <set>
#include <algorithm>
#define INF 0x3F3F3F3F
using namespace std;

struct Node{
    double c;//commission
    double r;//rate
    int point;
    int next;
}node[1010];
int size, head[1010];
int n, m, s;
double sq;

void add(int from, int to, double rate, double commission)
{
    node[size].r = rate;
    node[size].c = commission;
    node[size].point = to;
    node[size].next = head[from];
    head[from] = size++;
}
bool spfa()
{
    double dis[1010];
    int count[1010];
    bool vis[1010];
    memset(count, 0, sizeof count);
    memset(dis, 0, sizeof dis);
    memset(vis, false, sizeof vis);

    queue<int> q;
    q.push(s);
    dis[s] = sq;
    vis[s] = true;
    while(!q.empty()){
        int u = q.front();
        q.pop();
        vis[u] = false;
        for(int i = head[u]; ~i; i = node[i].next){
            int j = node[i].point;
            if(dis[j] < (dis[u] - node[i].c) * node[i].r){
                dis[j] = (dis[u] - node[i].c) * node[i].r;
                if(!vis[j]){
                    q.push(j);
                    vis[j] = true;
                    count[j]++;
                    if(count[j] > n) return true;
                }
            }
        }
    }
    return false;
}
int main()
{
    while(~scanf("%d%d%d%lf", &n, &m, &s, &sq)){
        size = 0;
        memset(head, -1, sizeof head);
        while(m--){
            int from, to;
            double r1, c1, r2, c2;
            scanf("%d%d%lf%lf%lf%lf", &from, &to, &r1, &c1, &r2, &c2);
            add(from, to, r1, c1);
            add(to, from, r2, c2);
            }
        if(spfa()) puts("YES");
        else puts("NO");
    }
    return 0;
}