Submission #21917

#	Time	Username	Problem	Language	Result	Execution time	Memory
21917		sampriti	Gap (APIO16_gap)	C++14	70 / 100	76 ms	7460 KiB

gap

#include "gap.h"

#include <climits>
#include <vector>

using namespace std;

long long binary_solve(long long L, long long R) {
  if(R - L <= 1) return R - L;

  int mid = (L + R)/2;
  long long qL1, qR1;
  MinMax(L + 1, mid, &qL1, &qR1);
  long long qL2, qR2;
  MinMax(mid + 1, R - 1, &qL2, &qR2);

  if(qL1 == -1 && qL2 == -1) return R - L;
  long long ans = 0;
  if(qL1 != -1 && qL2 != -1) ans = max(ans, qL2 - qR1);
  if(qL1 != -1) {
    ans = max(ans, qL1 - L);
    ans = max(ans, binary_solve(qL1, qR1));
  }
  if(qL2 != -1) {
    ans = max(ans, R - qR2);
    ans = max(ans, binary_solve(qL2, qR2));
  }
  return ans;
}

long long findGap(int T, int N) {
  long long L, R;
  MinMax(0, LLONG_MAX, &L, &R);

  if(T == 1) {
    return binary_solve(L, R);
  }


  long long diff = ((R - L - 1) + (N - 2))/(N - 1);

  vector<pair<long long, long long> > cands;
  cands.push_back({L, L});
  for(long long x = L + 1; x <= R - 1; x += diff) {
    long long qL, qR;
    MinMax(x, min(x + diff - 1, R - 1), &qL, &qR);
    if(qL != -1) cands.push_back({qL, qR});
  }
  cands.push_back({R, R});

  long long ans = 0;
  for(int i = 1; i < cands.size(); i++) {
    ans = max(ans, cands[i].first - cands[i - 1].second);
  }
  return ans;
}

Compilation message (stderr)

gap.cpp: In function 'long long int findGap(int, int)':
gap.cpp:52:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 1; i < cands.size(); i++) {
                    ^

• Subtask 1: 0 / 30
• Subtask 2: 70 / 70