01背包

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll N = 520*520;
ll n,k,a[N],c[N],dp[N],sum;//dp不能用重量范围太大了
int main()                 //下标变成攻击力 值是获取这么多攻击力花费的最少金币
{
    cin>>n>>k;
    for(ll i = 1;i<=n;i++)
        cin>>a[i]>>c[i],sum+=a[i];
    for (ll i = 0; i <= sum; i++) {
        dp[i] = 1e18;
    }
    dp[0] = 0;
    for(ll i = 1;i<=n;i++)//遍历每个商品
    {
        for(ll j = sum;j>=a[i];j--)
            dp[j] = min(dp[j],dp[j-a[i]]+c[i]);
    }
    for(ll i = sum;i>=0;i--)//找只花<=k金币时最大攻击力
    {
        if(dp[i]<=k)
        {
            cout<<i<<endl;
            return 0;
        }
    }
    
    return 0;
}