Submission #740049

#	Time	Username	Problem	Language	Result	Execution time	Memory
740049		fractlpaca	Horses (IOI15_horses)	C++17	77 / 100	1539 ms	64908 KiB

horses

#include "horses.h"
#include <vector>
#include <algorithm>
#include <set>
// #include <iostream>

#define v vector
#define ll long long
#define fi first
#define se second

#define MOD ((ll) 1000000007)
#define INF ((ll) 1000000001)

using namespace std;

int *x;
int *y;
int n;


// Editorial Subtask 5

v<ll> xs_mod;
// v<ll> xs_trunc;
v<int> ys_max;
set<pair<int, int>> ranges;

ll query_xs_mod(int L, int R, int l, int r, int index) {
	if (r<L || l>R) return 1;
	if (l>=L and r<=R) return xs_mod[index];
	int mid = (l+r)/2;
	ll subl = query_xs_mod(L, R, l, mid, index*2);
	ll subr = query_xs_mod(L, R, mid+1, r, index*2+1);
	return (subl*subr)%MOD;
}

void update_xs_mod(int pos, int value, int l, int r, int index) {
	int mid = (l+r)/2;
	if (l==r){
		xs_mod[index] = value;
		return;
	}
	if (pos <= mid){
		update_xs_mod(pos, value, l, mid, index*2);
	} else {
		update_xs_mod(pos, value, mid+1, r, index*2+1);
	}
	xs_mod[index] = (xs_mod[index*2]*xs_mod[index*2+1])%MOD;
}

int query_ys_max(int L, int R, int l, int r, int index) {
	if (r<L || l>R) return -1;
	if (l>=L and r<=R) return ys_max[index];
	int mid = (l+r)/2;
	int subl = query_ys_max(L, R, l, mid, index*2);
	int subr = query_ys_max(L, R, mid+1, r, index*2+1);
	if (subl == -1) return subr;
	if (subr == -1) return subl;
	if (y[subl] > y[subr]) return subl;
	return subr;
}

void update_ys_max(int pos, int value, int l, int r, int index) {
	if (l==r) {
		y[pos] = value;
		ys_max[index] = pos;
		return;
	}
	int mid = (l+r)/2;
	if (pos <= mid){
		update_ys_max(pos, value, l, mid, index*2);
	} else {
		update_ys_max(pos, value, mid+1, r, index*2+1);
	}
	int subl = ys_max[index*2];
	int subr = ys_max[index*2+1];
	int ans = 0;
	if (subl == -1) ans = subr;
	else if (subr == -1) ans = subl;
	else if (y[subl] > y[subr]) ans = subl;
	else ans = subr;
	ys_max[index] = ans;
}

int solve() {
	// cerr<<"Ranges: ";
	// for(auto it=ranges.begin(); it!=ranges.end(); it++) {
	// 	cerr<<"("<<it->fi<<", "<<it->se<<"), ";
	// } cerr<<endl;

	
	auto it = ranges.end();
	it--;
	int max_i = query_ys_max(it->fi, it->se, 0, n-1, 1);
	ll pop = x[max_i];
	it--;
	for(int counter=0; counter<60; counter++) {
		int i = query_ys_max(it->fi, it->se, 0, n-1, 1);
		if (y[i] > y[max_i]*pop) {
			max_i = i;
			pop=1;
		}
		pop = min(pop*x[i], INF);
		if (it==ranges.begin()) break;
		it--;
	}
	ll mult = query_xs_mod(0, max_i, 0, n-1, 1);
	return (int) ((mult*y[max_i])%MOD);
}

int init(int N, int X[], int Y[]) {
	n = N;
	x = X;
	y = Y;

	xs_mod = v<ll> (4*n, 1);
	//xs_trunc = v<ll> (4*n, 1);
	ys_max = v<int> (4*n, 1);

	for (int i=0; i<n; i++) {
		update_xs_mod(i, X[i], 0, n-1, 1);
		//update_xs_trunc(i, X[i], 0, n-1, 1);
		update_ys_max(i, Y[i], 0, n-1, 1);
		ranges.insert({i, i});
	}

	for(auto it = ranges.begin(); it!=ranges.end(); it++) {
		if (x[it->fi] == 1 && it!=ranges.begin()) {
			auto prev = it;
			prev--;
			if (x[prev->fi] == 1) {
				int new_start = prev->fi, new_end=it->se;
				ranges.erase(prev);
				ranges.erase(it);
				ranges.insert({new_start, new_end});
			}
		}
	}
	return solve();
}

int updateX(int pos, int val) {
	if (val == 1 && x[pos] != 1){
		auto it = ranges.find({pos, pos});
		int new_start = pos, new_end = pos;
		if (it!=ranges.begin()) {
			auto prev = it;
			prev--;
			if (x[prev->fi] == 1) {
				new_start = prev->fi;
				ranges.erase(prev);
			}
		}
		auto next = it;
		next++;
		if (next!=ranges.end()) {
			if (x[next->fi] == 1) {
				new_end = next->se;
				ranges.erase(next);
			}
		}
		ranges.erase(it);
		ranges.insert({new_start, new_end});

	} else if (val!=1 && x[pos] == 1) {
		auto it = ranges.upper_bound({pos, n});
		it--;
		int start = it->fi, end = it->se;
		if (pos > start) ranges.insert({start, pos-1});
		if (pos < end) ranges.insert({pos+1, end});
		ranges.erase(it);
		ranges.insert({pos, pos});
	}

	x[pos] = val;
	update_xs_mod(pos, val, 0, n-1, 1);
	//update_xs_trunc(pos, val, 0, n-1, 1);
	return solve();
}

int updateY(int pos, int val) {
	update_ys_max(pos, val, 0, n-1, 1);
	return solve();
}

• Subtask 1: 17 / 17
• Subtask 2: 17 / 17
• Subtask 3: 20 / 20
• Subtask 4: 23 / 23
• Subtask 5: 0 / 23