贪心 HDU3177

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <cmath>
 5 
 6 using namespace std;
 7 
 8 struct node
 9 {
10     int a,b;
11     bool operator <(node n) const
12     {
13         return b-a<n.b-n.a;
14     }
15 }bn[1100];
16 
17 int main()
18 {
19     int T;
20     scanf("%d",&T);
21     while(T--)
22     {
23         int v,n;
24         scanf("%d%d",&v,&n);
25         for(int i=0;i<n;i++)
26         {
27             scanf("%d%d",&bn[i].a,&bn[i].b);
28         }
29         sort(bn,bn+n);
30         int flag=-1;
31         for(int i=n-1;i>=0;i--)
32         {
33             if(v>=bn[i].b)
34             {
35                 v-=bn[i].a;
36             }
37             else
38             {
39                 flag=0;
40                 break;
41             }
42         }
43         if(flag)
44             cout<<"Yes"<<endl;
45         else
46             cout<<"No"<<endl;
47     }
48     return 0;
49 }
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