Problem p03833 (C++)

Buggy submission (status: Memory Limit Exceeded):
#include "bits/stdc++.h"

#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fr(x) freopen(x, "r", stdin)
#define fw(x) freopen(x, "w", stdout)
#define iout(x) printf("%d\n", x)
#define lout(x) printf("%lld\n", x)
#define REP(x, l, u) for (int x = (l); x <= (u); x++)
#define RREP(x, l, u) for (int x = (l); x >= (u); x--)
#define mst(x, a) memset(x, a, sizeof(x))
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define MP make_pair
#define se second
#define fi first
#define dbg(x) cout << #x << " = " << (x) << endl;
#define sz(x) ((int)x.size())
#define cl(x) x.clear()

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;
using namespace std;

const int maxn = 5010;
const int mod = 1e9 + 7;
const int MAX = 1000000010;
const double eps = 1e-6;
const double PI = acos(-1);

template <typename T> inline void read(T &x) {
  x = 0;
  T f = 1;
  char ch;
  do {
    ch = getchar();
    if (ch == '-')
      f = -1;
  } while (ch < '0' || ch > '9');
  do
    x = x * 10 + ch - '0', ch = getchar();
  while (ch <= '9' && ch >= '0');
  x *= f;
}

template <typename A, typename B> inline void read(A &x, B &y) {
  read(x);
  read(y);
}
template <typename A, typename B, typename C>
inline void read(A &x, B &y, C &z) {
  read(x);
  read(y);
  read(z);
}
template <typename A, typename B, typename C, typename D>
inline void read(A &x, B &y, C &z, D &w) {
  read(x);
  read(y);
  read(z);
  read(w);
}
template <typename A, typename B> inline A fexp(A x, B p) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mod)
    if (p & 1)
      ans = 1LL * ans * x % mod;
  return ans;
}
template <typename A, typename B> inline A fexp(A x, B p, A mo) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mo)
    if (p & 1)
      ans = 1LL * ans * x % mo;
  return ans;
}

int n, m;

ll A[maxn];

ll Ans[maxn][maxn], V[maxn][maxn];

int Q[maxn], bot;

int l[maxn], r[maxn];

void Work() {
  REP(j, 1, m) {
    bot = 0;
    Q[0] = 0;
    REP(i, 1, n) {
      while (bot && V[Q[bot]][j] < V[i][j])
        bot--;
      l[i] = Q[bot];
      Q[++bot] = i;
    }
    bot = 0;
    Q[0] = n + 1;
    RREP(i, n, 1) {
      while (bot && V[Q[bot]][j] <= V[i][j])
        bot--;
      r[i] = Q[bot];
      Q[++bot] = i;
    }
    REP(i, 1, n) {
      l[i]++;
      r[i]--;
      Ans[l[i]][i] += V[i][j];
      Ans[l[i]][r[i] + 1] -= V[i][j];
      Ans[i + 1][i] -= V[i][j];
      Ans[i + 1][r[i] + 1] += V[i][j];
    }
  }
  REP(i, 1, n)
  REP(j, 1, n) Ans[i][j] =
      Ans[i][j] + Ans[i - 1][j] + Ans[i][j - 1] - Ans[i - 1][j - 1];
  ll ans = 0;
  REP(i, 1, n) REP(j, i, n) ans = max(ans, Ans[i][j] - A[j] + A[i]);
  cout << ans << endl;
}

void Init() {
  read(n, m);
  REP(i, 2, n) read(A[i]), A[i] += A[i - 1];
  REP(i, 1, n) REP(j, 1, m) read(V[i][j]);
}

int main() {
  Init();
  Work();
  return 0;
}


Fixed submission:
#include "bits/stdc++.h"

#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fr(x) freopen(x, "r", stdin)
#define fw(x) freopen(x, "w", stdout)
#define iout(x) printf("%d\n", x)
#define lout(x) printf("%lld\n", x)
#define REP(x, l, u) for (int x = (l); x <= (u); x++)
#define RREP(x, l, u) for (int x = (l); x >= (u); x--)
#define mst(x, a) memset(x, a, sizeof(x))
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define MP make_pair
#define se second
#define fi first
#define dbg(x) cout << #x << " = " << (x) << endl;
#define sz(x) ((int)x.size())
#define cl(x) x.clear()

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;
using namespace std;

const int maxn = 5010;
const int mod = 1e9 + 7;
const int MAX = 1000000010;
const double eps = 1e-6;
const double PI = acos(-1);

template <typename T> inline void read(T &x) {
  x = 0;
  T f = 1;
  char ch;
  do {
    ch = getchar();
    if (ch == '-')
      f = -1;
  } while (ch < '0' || ch > '9');
  do
    x = x * 10 + ch - '0', ch = getchar();
  while (ch <= '9' && ch >= '0');
  x *= f;
}

template <typename A, typename B> inline void read(A &x, B &y) {
  read(x);
  read(y);
}
template <typename A, typename B, typename C>
inline void read(A &x, B &y, C &z) {
  read(x);
  read(y);
  read(z);
}
template <typename A, typename B, typename C, typename D>
inline void read(A &x, B &y, C &z, D &w) {
  read(x);
  read(y);
  read(z);
  read(w);
}
template <typename A, typename B> inline A fexp(A x, B p) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mod)
    if (p & 1)
      ans = 1LL * ans * x % mod;
  return ans;
}
template <typename A, typename B> inline A fexp(A x, B p, A mo) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mo)
    if (p & 1)
      ans = 1LL * ans * x % mo;
  return ans;
}

int n, m;

ll A[maxn];

ll Ans[maxn][maxn], V[maxn][210];

int Q[maxn], bot;

int l[maxn], r[maxn];

void Work() {
  REP(j, 1, m) {
    bot = 0;
    Q[0] = 0;
    REP(i, 1, n) {
      while (bot && V[Q[bot]][j] < V[i][j])
        bot--;
      l[i] = Q[bot];
      Q[++bot] = i;
    }
    bot = 0;
    Q[0] = n + 1;
    RREP(i, n, 1) {
      while (bot && V[Q[bot]][j] <= V[i][j])
        bot--;
      r[i] = Q[bot];
      Q[++bot] = i;
    }
    REP(i, 1, n) {
      l[i]++;
      r[i]--;
      Ans[l[i]][i] += V[i][j];
      Ans[l[i]][r[i] + 1] -= V[i][j];
      Ans[i + 1][i] -= V[i][j];
      Ans[i + 1][r[i] + 1] += V[i][j];
    }
  }
  REP(i, 1, n)
  REP(j, 1, n) Ans[i][j] =
      Ans[i][j] + Ans[i - 1][j] + Ans[i][j - 1] - Ans[i - 1][j - 1];
  ll ans = 0;
  REP(i, 1, n) REP(j, i, n) ans = max(ans, Ans[i][j] - A[j] + A[i]);
  cout << ans << endl;
}

void Init() {
  read(n, m);
  REP(i, 2, n) read(A[i]), A[i] += A[i - 1];
  REP(i, 1, n) REP(j, 1, m) read(V[i][j]);
}

int main() {
  Init();
  Work();
  return 0;
}