Submission #316331

#	Time	Username	Problem	Language	Result	Execution time	Memory
316331		nikatamliani	The Big Prize (IOI17_prize)	C++14	94.89 / 100	62 ms	5396 KiB

prize

#include <bits/stdc++.h>
using namespace std;
#include "prize.h"
vector < vector < int > > memo;
vector < int > memo_ask(int x) {
    if(!memo[x].empty()) return memo[x];
    return memo[x] = ask(x);
}
int find_best(int n) {
    int next = -1, at_most = min(472, n - 1);
    const int BLOCK_SIZE = 500;
    vector < int > bad(2); 
    memo.resize(n);
    int limit = 40, cnt = 0; 
    for(int i = 0; i <= at_most; ++i) {
        vector < int > cur = memo_ask(i);
        if(bad[0] + bad[1] <= cur[0] + cur[1]) bad = cur;
        if(cur[0] == 0 && cur[1] == 0) return i;
    }
  	for(int i = 0; i <= at_most; ++i) {
      	if(bad[0] + bad[1] != memo_ask(i)[0] + memo_ask(i)[1]) {
          	++cnt;
        }
  	}
  	vector < int > bad0 = bad, bad1(2);
  	if(cnt > limit) {
  	    for(int i = 0; i <= at_most; ++i) {
  	        if(bad[0] + bad[1] != memo_ask(i)[0] + memo_ask(i)[1]) {
  	            bad1 = memo_ask(i);
            }
  	    }
  	}
    for(int i = at_most + 1; i < n; i = next + 1) {
        int l = i, r = n - 1; next = -1;
        vector < int > t = memo_ask(i);
        if(t[0] + t[1] != bad0[0] + bad0[1]) {
            ++cnt;
            if(cnt <= limit) {
                if(bad1[0] + bad1[1] <= t[0] + t[1]) {
                    bad1 = t;
                }
            } else {
                bad1[0]++;
                bad1[1]--;
            }
            next = i;
            if(t[0] == 0 && t[1] == 0) return i; 
            continue;
        } 
        bad0 = t;
        int maybe = i + BLOCK_SIZE;
        if(maybe < n) {
            if(memo_ask(maybe) == bad0 || memo_ask(maybe) == bad1) {
                next = maybe; 
                continue;
            }
        }
        if(maybe < n) r = maybe - 1;
        while(r >= l) {
            int m = l + r >> 1;
            if(memo_ask(m) == bad0) {
                next = m;
                l = m + 1;
            } else {
                r = m - 1; 
            }
        }
        assert(next >= i);
    }
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:60:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |             int m = l + r >> 1;
      |                     ~~^~~
prize.cpp:12:25: warning: control reaches end of non-void function [-Wreturn-type]
   12 |     vector < int > bad(2);
      |                         ^

• Subtask 1: 20 / 20
• Subtask 2: 74.89 / 80