POJ 2060 Taxi Cab Scheme【最小路径覆盖】

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <vector>
 5 #include <cmath>
 6 using namespace std;
 7 
 8 const int maxn = 505;
 9 const int INF = 1000000000;
10 
11 int n;
12 int vis[maxn];
13 int Link[maxn];
14 vector<int> G[maxn];
15 bool Find(int u) {
16     for(int i = 0; i < G[u].size(); i++) {
17         int v = G[u][i];
18         if(!vis[v]) {
19             vis[v] = 1;
20             if(Link[v] == - 1 || Find(Link[v])) {
21                 Link[v] = u;
22                 return true;
23             }
24         }
25     }
26     return false;
27 }
28 
29 int solve() {
30     int cnt = 0;
31     memset(Link, -1, sizeof(Link));
32     for(int i = 1; i <= n; i++) {
33         if(G[i].size()) {
34             memset(vis, 0, sizeof(vis));
35             if(Find(i)) cnt++;
36         }
37     }
38     return cnt;
39 }
40 
41 int a[maxn], b[maxn], c[maxn], d[maxn], t[maxn];
42 bool check(int i, int j) {
43     if(t[j] - ((fabs(c[i] - a[i]) + fabs(d[i] - b[i]) + t[i]) + fabs(a[j] - c[i]) + fabs(b[j] - d[i])) >= 1) {
44         return true;
45     }
46     return false;
47 }
48 
49 int main() {
50     int tt;
51     int x, y;
52     scanf("%d",&tt);
53     while(tt--) {
54         scanf("%d",&n);
55         for(int i = 1; i <= n; i++) {
56             G[i].clear();
57             scanf("%d:%d",&x,&y);
58             t[i] = x * 60 + y;
59             scanf("%d %d %d %d",&a[i], &b[i], &c[i], &d[i]);
60         }
61         for(int i = 1; i <= n; i++) {
62             for(int j = 1; j <= n; j++) {
63                 if(i == j) continue;
64                 if(check(i, j)) {
65                     G[i].push_back(j);
66                 }
67             }
68         }
69         printf("%d\n", n - solve());
70     }
71     return 0;
72 }