背包？？？？不会。。。
1 #include<bits/stdc++.h> 2 #define INF 0x7fffffff 3 #define LL long long 4 #define N 100005 5 using namespace std; 6 inline int ra() 7 { 8 int x=0,f=1; char ch=getchar(); 9 while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();} 10 while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();} 11 return x*f; 12 } 13 struct node{int a,b;}a[N]; 14 LL f[2005][2005]; 15 bool cmp(node a, node b){return a.a>b.a;} 16 int main() 17 { 18 int n=ra(); 19 for (int i=1; i<=n; i++) a[i].a=ra(),a[i].b=ra(); 20 sort(a+1,a+n+1,cmp); 21 for (int i=0; i<=n; i++) for (int j=0; j<=n+1; j++) f[i][j]=-0x3f3f3f3f; f[0][1]=0; 22 for (int i=1; i<=n; i++) 23 for (int j=0; j<=n; j++) 24 f[i][j]=max(f[i-1][j],f[i-1][max(j-a[i].a,0)+1]+a[i].b); 25 LL ans=-0x3f3f3f3f; 26 for (int i=0; i<=n; i++) 27 ans=max(ans,f[n][i]); 28 cout<<ans; 29 return 0; 30 }