Submission #615825

#	Time	Username	Problem	Language	Result	Execution time	Memory
615825		IvanJ	The Big Prize (IOI17_prize)	C++17	20 / 100	9 ms	9852 KiB

prize

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

#define pb push_back
#define x first
#define y second

using namespace std;

typedef pair<int, int> ii;

const int maxn = 2e5 + 5;

vector<int> A[maxn];
vector<int> V;
int F = -1;
int cnt = 0;

void check(int x) {
	if(A[x][0] + A[x][1] == 0) F = x;
}

void find(int L, int R) {
	int lo = L, hi = R - 1;
	while(lo <= hi) {
		int mid = (lo + hi) / 2;
		if(A[mid].size() == 0) A[mid] = ask(mid);
		check(mid);
		if(F != -1) return;
		if(A[mid][0] + A[mid][1] < cnt) {V.pb(mid);return;}
		if(A[mid][1] == A[hi + 1][1]) hi = mid - 1;
		else lo = mid + 1;
	}
}

void solve(int lo, int hi, int R) {
	if(lo >= hi) return;
	if(R == 0) return;
	if(R == 1) {find(lo, hi);return;}
	
	int mid = (lo + hi) / 2;
	int mid1 = mid;
	while(1) {
		if(A[mid1].size() == 0) A[mid1] = ask(mid1);
		check(mid);
		if(F != -1) return;
		if(A[mid1][0] + A[mid1][1] < cnt) V.pb(mid1), mid1--;
		else break;
		if(mid1 < lo) break;
	}
	int R1, R2;
	if(mid1 == lo - 1) R2 = R - (mid - mid1);
	else R2 = A[mid1][1] - A[hi + 1][1] - (mid - mid1);
	R1 = R - R2;
	solve(lo, mid1 - 1, R1);
	solve(mid + 1, hi, R2);
}

int find_best(int n) {
	if(n <= 5000) {
		for(int i = 0;i < n;i++) {
			A[i] = ask(i);
			if(A[i][0] + A[i][1] == 0) return i;
		}
	}
	int pos = -1;
	int s = 470;
	for(int i = n - 1;i >= n - s;i--) {
		A[i] = ask(i);
		check(i);
		if(F != -1) return F;
		if(pos == -1 || A[i][0] + A[i][1] > A[pos][0] + A[pos][1])
			pos = i;
	}
	
	for(int i = pos + 1;i < n;i++) V.pb(i);
	cnt = A[pos][0];
	solve(0, pos - 1, A[pos][0]);
	return F;
}

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