poj1724

利用priority_queue进行广搜，每次弹出距离最短的，并把它能在最大费用内到达的点加入priority_queue

由于memset写得马虎，改了很久。

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

#define maxn 105
#define maxr 10005

struct Edge
{
    int v, c, l, next;
} edge[maxr];

struct Node
{
    int c, l, a;
    Node()
    {
    }
    Node(int cc, int ll, int aa): c(cc), l(ll), a(aa)
    {
    }
};

int n, m, r;
int head[maxn];
int ecount;

void addedge(int a, int b, int l, int c)
{
    edge[ecount].next = head[a];
    edge[ecount].v = b;
    edge[ecount].l = l;
    edge[ecount].c = c;
    head[a] = ecount;
    ecount++;
}

bool operator <(const Node &a, const Node &b)
{
    return a.l > b.l;
}

void work()
{
    priority_queue<Node> q;
    q.push(Node(0, 0, 1));
    while (!q.empty())
    {
        Node temp = q.top();
        q.pop();
        if (temp.a == n)
        {
            printf("%d\n", temp.l);
            return;
        }
        for (int i = head[temp.a]; i != -1; i = edge[i].next)
            if (temp.c + edge[i].c <= m)
                q.push(Node(temp.c + edge[i].c, temp.l + edge[i].l, edge[i].v));
    }
    printf("-1\n");
}

int main()
{
    //freopen("t.txt", "r", stdin);
    scanf("%d%d%d", &m, &n, &r);
    ecount = 0;
    memset(head, -1, sizeof(head));
    for (int i = 0; i < r; i++)
    {
        int a, b, c, d;
        scanf("%d%d%d%d", &a, &b, &c, &d);
        addedge(a, b, c, d);
    }
    work();
    return 0;
}