简单背包问题

#include<math.h>
#include<algorithm>
#include<time.h>
#include<stdlib.h>
#include<iostream>
#include<string.h>
#include<map>
#include<list>
#include<string>
#include<queue>
#include<set>
#include<vector>
#include<stack>
#include<limits>
#define re register
#define iosgo() std::ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
#define run(i,n) for (int i = 1; i <= n; i++)
#define cin std::cin
#define cout std::cout
#define ll long long
#define endl "\n"
using namespace std;
typedef pair<int, int>pll;
const int N = 2e5 + 10;
pll c[N];
int h[150][150];
int x[N], y[N], dp[N], ss[N];
int gcd(int a, int b)
{
    return b ? gcd(b, a % b) : a;
}
int a[N]; 
signed main()
{

    int n, sum;
    cin >> n >> sum;
    run(i, n)
    {
        cin >> x[i];
        cin >> y[i];
    }
    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        for (int j = sum; j >= 1; j--)
        {
            if (j >= x[i])
            {
                dp[j] = max(dp[j], dp[j - x[i]] + y[i]);
                ans = max(ans, dp[j]);
            }
        }
    }
    cout << ans << endl;
}