Submission #429264

#	Time	Username	Problem	Language	Result	Execution time	Memory
429264		Dremix10	The Big Prize (IOI17_prize)	C++17	0 / 100	15 ms	14652 KiB

prize

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pi;
typedef pair<ll,ll> pl;
#define endl '\n'
#define F first
#define S second
#define all(x) (x).begin(),(x).end()
const int N = 3e5+1;
const ll INF = 2e18;
const int MOD = 1e9+7;

vector<int> ask(int i);

vector<vector<int> > memo(N);

const int block = 5;
int nn;
int queried = 0;

set<int> sums;
bool done = false;
vector<int> askme(int i){
    if(memo[i].empty()){
        queried++;
        assert(queried <= 10000);
        memo[i] = ask(i);
        assert(done == false || sums.count(memo[i][0] + memo[i][1]));
    }
    return memo[i];
}

int seen,cheap;

int go(int b){
    for(int i=b*block;i<min(nn,(b+1)*block);i++){
        vector<int> arr = askme(i);
        if(arr[0] + arr[1] == 0)
            return i;
        if(arr[0] + arr[1] < cheap)
            seen++;
    }
    return -1;
}

int find_best(int n) {
    /// the second to smallest price is in at most 450 boxes
    /// the maximum amount of prizes is 5

    nn = n;
    int blocks = (n+4)/5;

    for(int i=0;i<min(500,n);i++){
        vector<int> arr = askme(i);
        cheap = max(cheap,arr[0] + arr[1]);
        sums.insert(arr[0] + arr[1]);
    }
    done = true;
    int L = 0,R = blocks-1;

    while(L<=R){
        int l = L,r = R;
        while(l<=r){
            int mid = (l+r)/2;
            int low,high,pos;

            pos = mid*block;
            vector<int> arr = askme(pos);
            low = arr[0],high = arr[1];
            if(low + high == 0)
                return pos;
            if(low + high < cheap){
                bool chk = 0;
                if(mid != 0){
                    vector<int> arr = askme(pos-1);
                    if(arr[0] + arr[1] < cheap || arr[0] - seen > 0)
                        chk = 1;
                    if(arr[0] + arr[1] == 0)
                        return pos-1;
                }
                if(chk){
                    r = mid-1;
                }
                else{
                    r = mid;
                    l = mid+1;
                }
                continue;
            }


            if(low - seen > 0)
                r = mid-1;
            else
                l = mid+1;
        }
        int ans = go(r);
        if(ans != -1)
            return ans;
        L = r+1;
    }



}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:106:1: warning: control reaches end of non-void function [-Wreturn-type]
  106 | }
      | ^

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