Problem p00154 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <fstream>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vint;
typedef pair<int, int> pint;
#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
template <class T> T RoundOff(T a) { return int(a + .5 - (a < 0)); }
template <class T, class C> void chmax(T &a, C b) {
  if (a < b)
    a = b;
}
template <class T, class C> void chmin(T &a, C b) {
  if (b < a)
    a = b;
}
template <class T, class C> pair<T, C> mp(T a, C b) { return make_pair(a, b); }

int main() {
  int m, g, a, b, n;
  while (cin >> m && m) {
    vector<vint> dp(m, vint(1001, 0));

    rep(i, m) {
      cin >> a >> b;

      if (i == 0) {
        for (int j = 0; j <= b && a * j <= 1000; j++) {
          dp[i][a * j]++;
        }
      } else {
        for (int j = 0; j <= b; j++) {
          for (int k = 0; k + a * j <= 1000; k++) {
            dp[i][k + a * j] += dp[i - 1][k];
          }
        }
      }
    }

    cin >> g;
    rep(i, g) {
      cin >> n;
      cout << dp[m - 1][n] << endl;
    }
  }
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <fstream>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vint;
typedef pair<int, int> pint;
#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
template <class T> T RoundOff(T a) { return int(a + .5 - (a < 0)); }
template <class T, class C> void chmax(T &a, C b) {
  if (a < b)
    a = b;
}
template <class T, class C> void chmin(T &a, C b) {
  if (b < a)
    a = b;
}
template <class T, class C> pair<T, C> mp(T a, C b) { return make_pair(a, b); }

int memo[101][1024];
int rec(vint &num, int v, int p) {
  if (v < 0)
    return 0;
  if (v == 0)
    return 1;
  if (p == 101)
    return 0;
  if (0 < memo[p][v])
    return memo[p][v];

  int res = 0;
  rep(i, num[p] + 1) res += rec(num, v - p * i, p + 1);

  return memo[p][v] = res;
}

int main() {
  int m, g, a, b, n;
  while (cin >> m && m) {
    vint num(128, 0);
    memset(memo, -1, sizeof memo);

    rep(i, m) {
      cin >> a >> b;
      num[a] += b;
    }

    cin >> g;
    rep(i, g) {
      cin >> n;
      cout << rec(num, n, 0) << endl;
    }
  }
}