poj_2267

不知道为什么就那才那么AC了。。。

后来想想，我在判断该边能不能加的时候确实是错了的。。

不过也不至于MLE啊。。。

MLE的好惨啊。。找不出错。。

一开始写的dijkstra，发现错了。。。并不是二维标记。。

然后改成spfa就行了。。

用的优先队列以及map映射，写起来还是挺好写的。。

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

const int maxn(111);
struct Edge{
    int v, start, end, time, next;
}e[maxn*10];
int head[maxn], cnt;
int num;
void init(){
    memset(head, -1, sizeof head);
    cnt = 0;
    num = 0;
}
void add_Edge(int u, int v, int start, int end, int time){
    e[cnt].v = v, e[cnt].start = start, e[cnt].end = end, e[cnt].time = time, e[cnt].next = head[u];
    head[u] = cnt++;
}
struct point{
    int end, blood;
    int u;
    friend bool operator < (const point &a, const point &b){
        return a.blood > b.blood;
    }
    point (int x, int y, int z): u(x),  end(y), blood(z) {}
};
int vis[maxn];
//priority_queue < point > q;
void spfa(int s, int t){
    priority_queue < point > q;
    //while(!q.empty()) q.pop();
    q.push(point(s, 18, 0));
    memset(vis, 0, sizeof vis);
    vis[s] = 1;
    while(!q.empty()){
        point tmp = q.top(); q.pop();
        int u = tmp.u;
        //if(vis[u]) continue;
        //vis[u] = 1;
        vis[u] = 0;
        if(u == t){
            printf("Vladimir needs %d litre(s) of blood.\n", tmp.blood);
            return;
        }
        for(int i = head[u]; i + 1; i = e[i].next){
            int v = e[i].v;
            int start = e[i].start;
            if((tmp.end < 18 && start < 18 && tmp.end <= start) || (tmp.end >= 18 &&(start >= tmp.end || start < 18)))
              q.push(point(v, e[i].end, tmp.blood));
            else
              q.push(point(v, e[i].end, tmp.blood + 1));
            if(!vis[v]) vis[v] = 1;
        }
    }
    puts("There is no route Vladimir can take.");
}
//map < string, int > mat;
int main(){
    int tcase;
    scanf("%d", &tcase);
    int z = 1;
    while(tcase --){
        int m;
        scanf("%d", &m);
        map < string, int > mat;
        //mat.clear();
        string s1, s2;
        int start, time;
        init();
        while(m --){
            cin>>s1>>s2>>start>>time;
            if(mat.count(s1) == 0) mat[s1] = num ++;
            if(mat.count(s2) == 0) mat[s2] = num ++;    
            start %= 24;
            if(!(start <= 6 && start + time <= 6 || start >= 18 && start + time <= 30))continue;
            //我的判断是错误的。。。改成别人写的，就AC了。。。
            //if((start % 24) >= 6 && (start % 24) < 18) continue;
            //if((start + time) % 24 > 6 && (start + time) % 24 < 18) continue;
            add_Edge(mat[s1], mat[s2], start%24, (start+time)%24, time);
        }
        cin>>s1>>s2;
        printf("Test Case %d.\n", z++);
        spfa(mat[s1], mat[s2]);
    }
    return 0;
}