Submission #316252

#	Time	Username	Problem	Language	Result	Execution time	Memory
316252		nikatamliani	The Big Prize (IOI17_prize)	C++14	90 / 100	76 ms	5428 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);
    vector < int > bad(2); 
    memo.resize(n);
    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;
    }
    int good = 0;
    for(int i = 0; i <= at_most; ++i) {
        if(bad != memo_ask(i)) ++good;
    }
    const int BLOCK_SIZE = (n - at_most - 1) / (at_most + 1 - good) + 1;
    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] != bad[0] + bad[1]) {
            next = i;
            if(t[0] == 0 && t[1] == 0) return i; 
            continue;
        } 
        int maybe = i + BLOCK_SIZE;
        if(maybe < n && memo_ask(maybe) == t) {
            next = maybe;
            continue;
        }
        if(maybe < n) r = maybe - 1;
        while(r >= l) {
            int m = l + r >> 1;
            vector < int > x = memo_ask(m);
            if(x == t) {
                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:40:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |             int m = l + r >> 1;
      |                     ~~^~~
prize.cpp:11:25: warning: control reaches end of non-void function [-Wreturn-type]
   11 |     vector < int > bad(2);
      |                         ^

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80