Submission #480717

#	Time	Username	Problem	Language	Result	Execution time	Memory
480717		Mackerel_Pike	The Kingdom of JOIOI (JOI17_joioi)	C++14	100 / 100	628 ms	54936 KiB

joioi

#include <bits/stdc++.h>

using namespace std;

const int maxn = 2005;

int n, m, mn, mx;
int a[maxn][maxn];
int l[maxn], r[maxn];

inline bool solve(int md){
  for(int i = 0; i < n; ++i){
    for(r[i] = -1; r[i] + 1 < m && a[i][r[i] + 1] >= mx - md; ++r[i]);
    for(l[i] = m; l[i] - 1 >= 0 && a[i][l[i] - 1] <= mn + md; --l[i]);
    --l[i];
    if(l[i] > r[i])
      return false;
  }
  int lst = -1; bool ok = true;
  for(int i = 0; i < n; ++i){
    lst = max(lst, l[i]);
    ok &= (lst <= r[i]);
  }
  if(ok)
    return true;
  lst = m;
  for(int i = 0; i < n; ++i){
    lst = min(lst, r[i]);
    if(lst < l[i])
      return false;
  }
  return true;
}

inline bool check(int md){
  if(solve(md))
    return true;
  for(int i = 0; i < n; ++i)
    reverse(a[i], a[i] + m);
  return solve(md);
}

int main(){
  //freopen("joioi.in", "r", stdin);
  
  scanf("%d%d", &n, &m);
  mx = 0, mn = 0x3f3f3f3f;
  
  for(int i = 0; i < n; ++i)
    for(int j = 0; j < m; ++j)
      scanf("%d", &a[i][j]), mx = max(mx, a[i][j]), mn = min(mn, a[i][j]);

  int lb = -1, rb = 1e9;
  for(; lb + 1 < rb; ){
    int md = lb + rb >> 1;
    if(check(md))
      rb = md;
    else
      lb = md;
  }

  printf("%d\n", rb);
  return 0;
}

Compilation message (stderr)

joioi.cpp: In function 'int main()':
joioi.cpp:55:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   55 |     int md = lb + rb >> 1;
      |              ~~~^~~~
joioi.cpp:46:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |   scanf("%d%d", &n, &m);
      |   ~~~~~^~~~~~~~~~~~~~~~
joioi.cpp:51:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |       scanf("%d", &a[i][j]), mx = max(mx, a[i][j]), mn = min(mn, a[i][j]);
      |       ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40