poj1062 昂贵的聘礼

/*
用物品为点建图，枚举交易范围，spfa
*/
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
#define ll long long
using namespace std;
const int maxn = 20005;
const ll inf = 987654321234LL;
int read(){
    char ch=getchar();
    int x=0,f=1;
    while(!(ch>=‘0‘&&ch<=‘9‘)){if(ch==‘-‘)f=-1;ch=getchar();};
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+(ch-‘0‘);ch=getchar();};
    return x*f;
}
struct edge{
    int v;
    int w;
    int nxt;
}e[maxn*3];
int n,m;
int cnt,head[maxn];
int p[maxn],l[maxn],sz[maxn];
int t,v;
int flag,vis[maxn];
ll dis[maxn],ans;
void ins(int u,int v,int w){
    cnt++;
    e[cnt].v = v;
    e[cnt].w = w;
    e[cnt].nxt = head[u];
    head[u] = cnt;
}
void spfa(int t){
    flag++;
    dis[0] = 0;
    for(int i = 1;i <= n;i++) dis[i] = inf;
    queue<int> q;
    vis[0] = flag;
    q.push(0);
    int now,to;
    while(!q.empty()){
        now = q.front();
        q.pop();
        for(int i = head[now];i;i = e[i].nxt){
            to = e[i].v;
            if(dis[to] > dis[now] + e[i].w && l[to] >= t && l[to] <= t+m){
                dis[to] = dis[now] + e[i].w;
                if(vis[to] != flag){
                    vis[to] = flag;
                    q.push(to);
                }
            }
        }
        vis[now] = false;
    }
    ans = min(ans,dis[1]);
}
int main(){
    m = read();
    n = read();
    for(int i = 1;i <= n;i++){
        p[i] = read();
        l[i] = read();
        sz[i] = read();
        ins(0,i,p[i]);
        for(int j = 1;j <= sz[i];j++){
            t = read();
            v = read();
            ins(t,i,v);
        }
    }
    ans = inf;
    for(int i = l[1] - m;i <= l[1];i++) spfa(i);
    cout<<ans;
    return 0;
}