HDU3697 Selecting courses

　　原題傳送：http://acm.hdu.edu.cn/showproblem.php?pid=3697

　　貪心算法。起始點可能是0,1,2,3,4，枚舉這5個起始點，後面的點選擇可選政策是：選擇符合該時刻且結束時間最早的。

View Code

1 #include <stdio.h>
 2 #include <string.h>
 3 #define N 305
 4 struct course
 5 {
 6     int s, t;
 7 }e[N];
 8 
 9 int n;
10 bool vis[N];
11 
12 void work()
13 {
14     int ans, i, j, k, x, max;
15     max = 0;
16     for(i = 0; i < 5; i ++)
17     {
18         memset(vis, false, sizeof vis);
19         ans = 0;
20         for(j = i; j <= 1000; j += 5)
21         {
22             x = -1;
23             for(k = 0; k < n; k ++)
24             {
25                 if(!vis[k] && e[k].s <= j && e[k].t > j)
26                     if(x == -1 || e[k].t < e[x].t)
27                         x = k;
28             }
29             if(x != -1)
30                 ans ++, vis[x] = true;
31         }
32         if(ans > max)
33             max = ans;
34     }
35     printf("%d\n", max);
36 }
37 
38 void read()
39 {
40     for(int i = 0; i < n; i ++)
41         scanf("%d%d", &e[i].s, &e[i].t);
42 }
43 
44 int main()
45 {
46     while(scanf("%d", &n), n)
47     {
48         read();
49         work(); 
50     }
51     return 0;
52 }      

轉載于:https://www.cnblogs.com/huangfeihome/archive/2012/09/13/2683096.html