Submission #981047

#	Time	Username	Problem	Language	Result	Execution time	Memory
981047		kilkuwu	Rice Hub (IOI11_ricehub)	C++17	100 / 100	9 ms	4508 KiB

ricehub

#include "ricehub.h"

#include <bits/stdc++.h>

int besthub(int R, int L, int X[], long long B) { 
  std::vector<int64_t> pref(R + 1);
  for (int i = 0; i < R; i++) {
    pref[i + 1] = pref[i] + X[i];
  }


  auto check = [&](int mid) -> bool {
    // 3 / 2 = 1
    // 4 / 2 = 2 
    // 0 1 2 3 
    int elem = mid / 2;
    int num_left = elem;
    int num_right = mid - num_left;
    for (int i = 0; i + mid <= R; i++) {
      int64_t me = X[i + elem];
      auto sum_left = pref[i + elem] - pref[i]; // i -> 
      auto sum_right = pref[i + mid] - pref[i + elem];
      auto ans = me * num_left - sum_left + sum_right - me * num_right;
      if (ans <= B) return true;
    } 
    return false;
  };

  int ans = 0;
  int lb = 1, rb = R;

  while (lb <= rb) {
    int mb = (lb + rb) / 2;
    if (check(mb)) {
      ans = mb;
      lb = mb + 1;
    } else {
      rb = mb - 1;
    }
  }

  return ans;
}

#ifdef LOCAL 
#include "ricehub.h"
#include <stdio.h>
#include <stdlib.h>

#define MAX_R  1000000

static int R, L;
static long long B;
static int X[MAX_R];
static int solution;

inline 
void my_assert(int e) {if (!e) abort();}

static void read_input()
{
  int i;
  my_assert(3==scanf("%d %d %lld",&R,&L,&B));
  for(i=0; i<R; i++)
    my_assert(1==scanf("%d",&X[i]));
  my_assert(1==scanf("%d",&solution));
}

int main()
{
  int ans;
  read_input();
  ans = besthub(R,L,X,B);
  if(ans==solution)
    printf("Correct.\n");
  else
    printf("Incorrect.  Returned %d instead of %d.\n",ans,solution);

  return 0;
}
#endif

• Subtask 1: 17 / 17
• Subtask 2: 25 / 25
• Subtask 3: 26 / 26
• Subtask 4: 32 / 32