HDU 3697贪心

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 
 7 struct Node
 8 {
 9     int l, r;
10 } node[400];
11 
12 int cmp(Node a, Node b)
13 {
14     if (a.r != b.r) return a.r <b.r;
15     return a.l <= b.l;
16 }
17 
18 int main()
19 {
20     int n;
21     while(cin >> n)
22     {
23         if (n == 0) break;
24         for (int i=0; i<n; ++i)
25         {
26             cin >> node[i].l >> node[i].r;
27         }
28         sort(node, node+n, cmp);
29         int ans = 0;
30         int vis[400];
31         memset(vis, 0, sizeof(vis));
32 
33         for (int i=0; i<5; ++i)
34         {
35             int st = i;
36             int tans = 0;
37             memset(vis, 0, sizeof(vis));
38             //for (st=i; st<=node[n-1].r; st+=5)
39             while(st <= node[n-1].r)
40             {
41                 for (int j=0; j<n; ++j)
42                 {
43                     if (vis[j]) continue;
44                     if (node[j].l < st && node[j].r >= st)
45                     {
46                         //st += 5;
47                         vis[j] = 1;
48                         tans += 1;
49                         break;
50                     }
51                     //st += 5;
52                 }
53                 st += 5;
54             }
55             ans = max(ans, tans);
56         }
57         cout << ans << endl;
58     }
59     return 0;
60 }