Submission #36592

#	Time	Username	Problem	Language	Result	Execution time	Memory
36592		ruhanhabib39	The Big Prize (IOI17_prize)	C++14	20 / 100	73 ms	6968 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>

// 123
const int MAXN = 2e5;

std::vector<int> res[MAXN + 10];

std::pair<int,int> get(int i) {
   if(!res[i].size()) res[i] = ask(i);
   return {res[i][0], res[i][1]};
}

int sum(int i) {
   return get(i).first + get(i).second;
}

int ls = 0;

int lowest(int n) {
   int mx = 0;
   for(int i = 0; i*i <= n; i++) {
      mx = std::max(mx, sum(i));
   }
   return mx;
}

int solve(int lo, int hi, int lc, int cc) {
   if(cc == 0) return -1;
   assert(lo <= hi && cc > 0);
   if(cc == hi-lo+1) {
      for(int i = lo; i <= hi; i++) {
         if(sum(i) == 0) return i;
      }
      return -1;
   }
   int ml = (lo + hi) / 2 + 1, mr = (lo + hi) / 2;
   int lf;
   for(int i = 0; i < hi-lo+1; i++) {
      int q;
      if(i % 2 == 0) q = --ml;
      else q = ++mr;
      if(sum(q) == ls) {
         if(i % 2 == 0) lf = get(q).first - lc;
         else lf = get(q).first - lc - (mr - ml);
         break;
      } else if(sum(q) == 0) {
         return q;
      }
   }
   
   int rr = solve(lo, ml-1, lc, lf);
   if(rr != -1) return rr;

   rr = solve(mr+1, hi, lc + (mr - ml) + lf, cc - lf - (mr - ml));
   if(rr != -1) return rr;

   return -1;
}

int find_best(int n) {
   ls = lowest(n); 
   return solve(0, n-1, 0, ls);
}

Compilation message (stderr)

prize.cpp: In function 'int solve(int, int, int, int)':
prize.cpp:55:14: warning: 'lf' may be used uninitialized in this function [-Wmaybe-uninitialized]
    rr = solve(mr+1, hi, lc + (mr - ml) + lf, cc - lf - (mr - ml));
              ^

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80