Problem p03833 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define MAX 5003
#define reg register

using namespace std;

int n, m;
int p[MAX][205], cur_max[205], upper[205];
long long dis[MAX];

inline int Rd() {
  int x = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9')
    ch = getchar();
  while (ch >= '0' && ch <= '9')
    x = x * 10 + ch - '0', ch = getchar();
  return x;
}
inline void ChkMax(long long &aa, long long bb) {
  if (aa < bb)
    aa = bb;
  return;
}

int main() {
  n = Rd(), m = Rd();
  for (reg int i = 2; i <= n; ++i) {
    dis[i] = Rd();
    dis[i] += dis[i - 1];
  }
  for (reg int i = 1; i <= n; ++i) {
    for (reg int j = 1; j <= m; ++j) {
      p[i][j] = Rd();
      if (upper[j] < p[i][j])
        upper[j] = p[i][j];
    }
  }
  long long maxp = 0;
  for (reg int i = 1; i <= m; ++i)
    maxp += upper[i];
  reg long long ans = 0, cur_p = 0;
  for (reg int i = 1; i <= n; ++i) {
    cur_p = 0;
    memset(cur_max, 0, sizeof cur_max);
    for (reg int j = i; j <= n; ++j) {
      for (reg int k = 1; k <= m; ++k) {
        if (p[j][k] > cur_max[k]) {
          cur_p += p[j][k] - cur_max[k];
          cur_max[k] = p[j][k];
        }
      }
      if (maxp - (dis[j] - dis[i]) <= ans)
        break;
      ChkMax(ans, cur_p - (dis[j] - dis[i]));
    }
  }
  cout << ans << endl;
  return 0;
}

Fixed submission:
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#include <bits/stdc++.h>
#define MAX 5003
#define reg register

using namespace std;

int n, m;
int p[MAX][205], cur_max[205], upper[205];
long long dis[MAX];

inline int Rd() {
  int x = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9')
    ch = getchar();
  while (ch >= '0' && ch <= '9')
    x = x * 10 + ch - '0', ch = getchar();
  return x;
}
inline void ChkMax(long long &aa, long long bb) {
  if (aa < bb)
    aa = bb;
  return;
}

int main() {
  n = Rd(), m = Rd();
  for (reg int i = 2; i <= n; ++i) {
    dis[i] = Rd();
    dis[i] += dis[i - 1];
  }
  for (reg int i = 1; i <= n; ++i) {
    for (reg int j = 1; j <= m; ++j) {
      p[i][j] = Rd();
      if (upper[j] < p[i][j])
        upper[j] = p[i][j];
    }
  }
  long long maxp = 0;
  for (reg int i = 1; i <= m; ++i)
    maxp += upper[i];
  reg long long ans = 0, cur_p = 0;
  for (reg int i = 1; i <= n; ++i) {
    cur_p = 0;
    memset(cur_max, 0, sizeof cur_max);
    for (reg int j = i; j <= n; ++j) {
      for (reg int k = 1; k <= m; ++k) {
        if (p[j][k] > cur_max[k]) {
          cur_p += p[j][k] - cur_max[k];
          cur_max[k] = p[j][k];
        }
      }
      if (maxp - (dis[j] - dis[i]) <= ans)
        break;
      ChkMax(ans, cur_p - (dis[j] - dis[i]));
    }
  }
  cout << ans << endl;
  return 0;
}