Problem p01088 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

#define _overload(_1, _2, _3, name, ...) name
#define _rep(i, n) _range(i, 0, n)
#define _range(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define rep(...) _overload(__VA_ARGS__, _range, _rep, )(__VA_ARGS__)

#define _rrep(i, n) _rrange(i, n, 0)
#define _rrange(i, a, b) for (int i = (int)(a)-1; i >= (int)(b); --i)
#define rrep(...) _overload(__VA_ARGS__, _rrange, _rrep, )(__VA_ARGS__)

#define _all(arg) begin(arg), end(arg)
#define uniq(arg) sort(_all(arg)), (arg).erase(unique(_all(arg)), end(arg))
#define getidx(ary, key) lower_bound(_all(ary), key) - begin(ary)
#define clr(a, b) memset((a), (b), sizeof(a))
#define bit(n) (1LL << (n))

// #define DEBUG

#ifdef DEBUG
#define dump(...) fprintf(stderr, __VA_ARGS__)
#else
#define dump(...)
#endif

template <class T> bool chmax(T &a, const T &b) {
  return (a < b) ? (a = b, 1) : 0;
}
template <class T> bool chmin(T &a, const T &b) {
  return (b < a) ? (a = b, 1) : 0;
}

using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;

const double EPS = 1e-10;
const double PI = acos(-1.0);
const int inf = 1 << 30;
const ll mod = 1000000007LL;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

ll extgcd(ll a, ll b, ll &x, ll &y) {
  x = 1, y = 0;
  ll g = a;
  if (b != 0)
    g = extgcd(b, a % b, y, x), y -= a / b * x;
  return g;
}
ll ADD(const ll &a, const ll &b, const ll &mod) { return (a + b) % mod; }
ll SUB(const ll &a, const ll &b, const ll &mod) { return (a - b + mod) % mod; }
ll MUL(const ll &a, const ll &b, const ll &mod) { return (1LL * a * b) % mod; }
ll DIV(const ll &a, const ll &b, const ll &mod) {
  ll x, y;
  extgcd(b, mod, x, y);
  return MUL(a, (x + mod) % mod, mod);
}

random_device rd;
mt19937 mt(rd());
uniform_int_distribution<int> dice(1, 6);
uniform_real_distribution<double> score(0.0, 10.0);

const int N = 101;
const int M = 50010;

using Elem = tuple<int, int>;
Elem dp[N][M];

int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);

  for (int n; cin >> n, n;) {
    vi a(n);
    for (auto &e : a)
      cin >> e;

    rep(i, n + 1) rep(j, M) dp[i][j] = Elem(-1, -1);
    dp[0][0] = Elem(0, 0);

    rep(i, n) {
      int org = a[i];
      int price = org % 1000;
      rep(j, M) {
        Elem cur = dp[i][j];
        int num, total;
        tie(num, total) = cur;
        if (num == -1)
          continue;

        if (price == 0) {
          chmax(dp[i + 1][j], cur);
          int diff = (price + 500) % 1000;
          if (j - diff >= 0) {
            chmax(dp[i + 1][j - diff], Elem(num + 1, total - org)); // ?
          }
        } else if (price <= 500) {
          chmax(dp[i + 1][min(M, j + 500 - price)], Elem(num + 1, total - org));
        } else {
          chmax(dp[i + 1][j], cur);
          chmax(dp[i + 1][min(M, j + 1000 - price)], Elem(num, total - org));
          int diff = (price + 500) % 1000;
          if (j - diff >= 0) {
            chmax(dp[i + 1][j - diff], Elem(num + 1, total - org));
          }
        }
      }
    }

    Elem res(0, 0);
    rep(i, n + 1) {
      rep(j, M) { chmax(res, dp[i][j]); }
    }
    cout << get<0>(res) << " " << -get<1>(res) << endl;
  }

  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>

#define _overload(_1, _2, _3, name, ...) name
#define _rep(i, n) _range(i, 0, n)
#define _range(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define rep(...) _overload(__VA_ARGS__, _range, _rep, )(__VA_ARGS__)

#define _rrep(i, n) _rrange(i, n, 0)
#define _rrange(i, a, b) for (int i = (int)(a)-1; i >= (int)(b); --i)
#define rrep(...) _overload(__VA_ARGS__, _rrange, _rrep, )(__VA_ARGS__)

#define _all(arg) begin(arg), end(arg)
#define uniq(arg) sort(_all(arg)), (arg).erase(unique(_all(arg)), end(arg))
#define getidx(ary, key) lower_bound(_all(ary), key) - begin(ary)
#define clr(a, b) memset((a), (b), sizeof(a))
#define bit(n) (1LL << (n))

// #define DEBUG

#ifdef DEBUG
#define dump(...) fprintf(stderr, __VA_ARGS__)
#else
#define dump(...)
#endif

template <class T> bool chmax(T &a, const T &b) {
  return (a < b) ? (a = b, 1) : 0;
}
template <class T> bool chmin(T &a, const T &b) {
  return (b < a) ? (a = b, 1) : 0;
}

using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;

const double EPS = 1e-10;
const double PI = acos(-1.0);
const int inf = 1 << 30;
const ll mod = 1000000007LL;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

ll extgcd(ll a, ll b, ll &x, ll &y) {
  x = 1, y = 0;
  ll g = a;
  if (b != 0)
    g = extgcd(b, a % b, y, x), y -= a / b * x;
  return g;
}
ll ADD(const ll &a, const ll &b, const ll &mod) { return (a + b) % mod; }
ll SUB(const ll &a, const ll &b, const ll &mod) { return (a - b + mod) % mod; }
ll MUL(const ll &a, const ll &b, const ll &mod) { return (1LL * a * b) % mod; }
ll DIV(const ll &a, const ll &b, const ll &mod) {
  ll x, y;
  extgcd(b, mod, x, y);
  return MUL(a, (x + mod) % mod, mod);
}

random_device rd;
mt19937 mt(rd());
uniform_int_distribution<int> dice(1, 6);
uniform_real_distribution<double> score(0.0, 10.0);

const int N = 101;
const int M = 5010;

int dp[N][M][N];

int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);

  for (int n; cin >> n, n;) {
    vi a(n);
    for (auto &e : a)
      cin >> e;

    rep(i, n + 1) rep(k, n + 1) rep(j, M) dp[i][j][k] = inf;
    dp[0][0][0] = 0;

    rep(i, n) {
      int org = a[i];
      int price = org % 1000;
      rep(k, n) {
        rep(j, M) {
          int cur = dp[i][j][k];
          if (cur == inf)
            continue;

          if (price == 0) {
            chmin(dp[i + 1][j][k], cur);
            int diff = (price + 500) % 1000;
            if (j - diff >= 0) {
              chmin(dp[i + 1][j - diff][k + 1], cur + org);
            }
          } else if (price <= 500) {
            chmin(dp[i + 1][min(M, j + 500 - price)][k + 1], cur + org);
          } else {
            chmin(dp[i + 1][j][k], cur);
            chmin(dp[i + 1][min(M, j + 1000 - price)][k], cur + org);
            int diff = (price + 500) % 1000;
            if (j - diff >= 0) {
              chmin(dp[i + 1][j - diff][k + 1], cur + org);
            }
          }
        }
      }
    }

    pair<int, int> res(-1, -1);
    rep(i, n + 1) {
      rep(k, n + 1) {
        rep(j, M) {
          if (dp[i][j][k] == inf)
            continue;
          chmax(res, pair<int, int>(k, -dp[i][j][k]));
        }
      }
    }
    cout << res.first << " " << -res.second << endl;
  }

  return 0;
}