Problem p03163 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define ff first
#define ss second
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define vi vector<int>
#define mii map<int, int>
#define pqb priority_queue<int>
#define pqs priority_queue<int, vi, greater<int>>
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define ps(x, y) fixed << setprecision(y) << x
#define mk(arr, n, type) type *arr = new type[n];
#define w(x)                                                                   \
  int x;                                                                       \
  cin >> x;                                                                    \
  while (x--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    pbds;

void dk() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif
}
int knapsack(int a[], int val[], int n, int k) {
  int dp[k + 1][n + 1];
  for (int i = 0; i <= n; i++) {
    dp[0][i] = 0;
  }
  for (int i = 0; i <= k; i++) {
    dp[i][0] = 0;
  }
  for (int i = 1; i <= k; i++) {
    for (int j = 1; j <= n; j++) {
      if (a[j - 1] <= i) {
        dp[i][j] = max(dp[i][j - 1], dp[i - a[j - 1]][j - 1] + val[j - 1]);
      } else {
        dp[i][j] = dp[i][j - 1];
      }
      // cout << dp[i][j] << " ";
    }
    // cout << endl;
  }
  return dp[k][n];
}
int32_t main() {
  dk();
  int n, k;
  cin >> n >> k;
  int val[n], a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> val[i];
  }
  int m = knapsack(a, val, n, k);
  cout << m;
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define ff first
#define ss second
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define vi vector<int>
#define mii map<int, int>
#define pqb priority_queue<int>
#define pqs priority_queue<int, vi, greater<int>>
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define ps(x, y) fixed << setprecision(y) << x
#define mk(arr, n, type) type *arr = new type[n];
#define w(x)                                                                   \
  int x;                                                                       \
  cin >> x;                                                                    \
  while (x--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    pbds;

void dk() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif
}
int knapsack(int a[], int val[], int n, int k) {
  int dp[k + 1][n + 1];
  for (int i = 0; i <= n; i++) {
    dp[0][i] = 0;
  }
  for (int i = 0; i <= k; i++) {
    dp[i][0] = 0;
  }
  for (int i = 1; i <= k; i++) {
    for (int j = 1; j <= n; j++) {
      if (a[j - 1] <= i) {
        dp[i][j] = max(dp[i][j - 1], dp[i - a[j - 1]][j - 1] + val[j - 1]);
      } else {
        dp[i][j] = dp[i][j - 1];
      }
      // cout << dp[i][j] << " ";
    }
    // cout << endl;
  }
  return dp[k][n];
}
int32_t main() {
  // dk();
  int n, k;
  cin >> n >> k;
  int val[n], a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> val[i];
  }
  int m = knapsack(a, val, n, k);
  cout << m;
  return 0;
}