Submission #247355

#	Time	Username	Problem	Language	Result	Execution time	Memory
247355		hhh07	The Big Prize (IOI17_prize)	C++14	20 / 100	64 ms	10436 KiB

prize

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <utility>
#include <set>
#include <cmath>
#include <cstring>
#include "prize.h"
 
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef pair<ll, ll> ii;
 
vi mem[(int)2e5 + 1];
bool done[(int)2e5 + 1];
 
vi pitaj(int idx){
    if (done[idx])
        return mem[idx];
    done[idx] = true;
    return mem[idx] = ask(idx);
}
 
int smanji(int x, int y, int t, int maxi){
    while(t*y >= t*x){
        vi r = pitaj(y);
        if (r[0] + r[1] == 0)
            return -(y + 1);
        if (r[0] + r[1] == maxi)
            break;
        y += -t;
    }
    return y;
}
 
int bin_search(int lijevo, int beg, int end, int maxi){
    if (beg > end)
        return -1;
    int l = beg, r = end;
    vi t;
    while(l < r){
        int mid = (l + r)/2;
        t = pitaj(mid);
        if (t[0] + t[1] == 0)
            return mid;
        if (t[0] + t[1] == maxi){
            if (lijevo - t[1])
                r = mid - 1;
            else
                l = mid + 1;
        }
        else
            r = mid;
    }
    
    l = smanji(end, l, -1, maxi);
    if (l < 0)
        return - l - 1;
    if (mem[l][1] - mem[end + 1][1])
        return bin_search(mem[l][1], l + 1, end, maxi);
    return -1;
}
 
 
int find_best(int n){
    memset(done, false, sizeof done);
    int maxi = -1;
    int grupa = 460, br = n/460;
    int curr = 0;
    vi idx;
    for (int i = 0; i < grupa; i++){
        vi res = pitaj(curr);
        maxi = max(maxi, res[0] + res[1]);
        if (res[0] + res[1] == 0)
            return curr;
        idx.push_back(curr);
        curr += br;
        if (i < (n%460))
            curr++;
        
    }
    done[n] = true; mem[n] = {maxi, 0}; idx.push_back(n);
    vi r;
    for (int i = 0; i < idx.size() - 1; i++){
        int x = idx[i], y = idx[i + 1];
        int res = -1;
        x = smanji(y, x, -1, maxi); y = smanji(x, y, 1, maxi);
        if (x < 0)
            return - x - 1;
        if (y < 0)
            return - y - 1;
        if (mem[x][1] - mem[y][1])
                res = bin_search(mem[x][1], x + 1, y - 1, maxi);
        if (res != -1)
            return res;
    }
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:87:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < idx.size() - 1; i++){
                     ~~^~~~~~~~~~~~~~~~
prize.cpp:100:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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