笔直的水管 usaco 背包

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<string>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<iomanip>
 7 #include<cstdlib>
 8 using namespace std;
 9 const int maxn=101000;
10 const int inf=100000000;
11 int L,n;
12 int w[maxn],v[maxn],c[maxn];
13 void init(){
14     scanf("%d%d",&L,&n);
15     for(int i=1;i<=n;i++)scanf("%d%d",&w[i],&v[i]);
16 }
17 void work(){
18     memset(c,-10,sizeof(c));
19     c[0]=inf;
20     for(int i=1;i<=n;i++)
21         for(int j=L;j>=0;j--){
22             if(j<w[i])break;
23             c[j]=max(c[j],min(c[j-w[i]],v[i]));
24         }
25     cout<<c[L]<<endl;
26 }
27 int main(){
28     init();
29     work();
30 }