제출 #247448

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
247448		ernestvw	말 (IOI15_horses)	C++11	0 / 100	1594 ms	77360 KiB

horses

#include <bits/stdc++.h>
using namespace std;

using ll = long long;

const ll mod = 1e9 + 7;

int n;
vector<ll> C, P;

ll preprod = 1;

ll fp(ll x, ll y){
	ll res=1;
	while(y){
		if(y%2LL)res*=x;
		res%=mod;
		x*=x;
		x%=mod;
		y/=2LL;
	}
	return res;
}

ll inv(ll x){return fp(x,mod-2LL);}

set<int> _indices, _negindices;

int prochain(int i) {
	if(_indices.size() == 0 || i >= *_indices.rbegin()) return n;
	return *lower_bound(_indices.begin(), _indices.end(), i + 1);
}

int precedent(int i) {
	if(_negindices.size() == 0 || -i >= *_indices.rbegin()) return -1;
	return -*lower_bound(_negindices.begin(), _negindices.end(), -i+1);
}

ll treeProd[4000000],treeMax[4000000];

void updateProd(int l, int r, int idx, int i, ll val) {
	if(idx < l || r < idx || r < l) return;
	if(l == r) {
		treeProd[i] = val;
		return;
	}
	updateProd(l, (l+r)/2, idx, 2*i+1, val);
	updateProd((l+r)/2+1, r, idx, 2*i+2, val);
	treeProd[i] = treeProd[2*i+1] * treeProd[2*i+2];
	treeProd[i] %= mod;
}

ll getProd(int l, int r, int L, int R, int i) {
	if(R < l || L > r || r < l) return 1;
	if(L <= l && r <= R) return treeProd[i];
	return (getProd(l, (l+r)/2, L, R, 2*i+1) * getProd((l+r)/2+1, r, L, R, 2*i+2)) % mod;
}

void updateMax(int l, int r, int idx, int i, ll val) {
	if(idx < l || r < idx || r < l) return;
	if(l == r) {
		treeMax[i] = val;
		return;
	}
	updateMax(l, (l+r)/2, idx, 2*i+1, val);
	updateMax((l+r)/2+1, r, idx, 2*i+2, val);
	treeMax[i] = max(treeMax[2*i+1], treeMax[2*i+2]);
}

ll getMax(int l, int r, int L, int R, int i) {
	if(R < l || L > r || r < l) return 0;
	if(L <= l && r <= R) return treeMax[i];
	return max(getMax(l, (l+r)/2, L, R, 2*i+1), getMax((l+r)/2+1, r, L, R, 2*i+2));
}

int solve2() {
	ll prod = C[n - 1];
	int best = n - 1;
	long double ldprod = (long double)C[n-1];
	for(int i = n - 2; i >= 0; --i) {
		prod *= C[i];
		ldprod *= C[i];
		long double x = ldprod * (long double)P[best];
		if(x >= 1.5e18) break;
		if(prod * P[best] <= C[i] * P[i]) {
			best = i;
			prod = C[i];
			ldprod = (long double)C[i];
		}
	}
	prod = 1;
	if(n > 1000) {
		prod = preprod;
		for(int i = n - 100; i <= best; ++i)
			prod = (prod * C[i]) % mod;
		prod = (prod * P[best]) % mod;
		return int(prod % mod);
	}
	for(int i = 0; i <= best; ++i) {
		prod *= C[i];
		prod %= mod;
	}
	prod *= P[best];
	prod %= mod;
	return int(prod % mod);
}

int solve() {
	ll prod = C[n - 1];
	int best = n - 1;
	long double ldprod = (long double)C[n-1];
	ll pbest = P[n - 1];
	int i = precedent(n - 1);
	while(i >= 0) {
		prod *= C[i];
		ldprod *= (long double)C[i];
		ll p = getMax(0, n-1, i, prochain(i) - 1, 0);
		long double x = ldprod * (long double)pbest;
		if(x >= 1.5e18) break;
		if(prod * pbest <= C[i] * p) {
			best = i;
			prod = C[i];
			pbest = p;
			ldprod = (long double)C[i];
		}
		i = precedent(i);
	}
	prod = getProd(0, n-1, 0, best, 0);
	prod *= pbest;
	prod %= mod;
	return int(prod);
}

int init2(int N, int X[], int Y[]) {
	n = N;
	C.resize(n);
	P.resize(n);
	for(int i = 0; i < n; ++i) C[i] = X[i];
	for(int i = 0; i < n; ++i) P[i] = Y[i];
	if(n > 1000) {
		preprod = 1;
		for(int i = 0; i < n - 100; ++i) {
			preprod *= C[i];
			preprod %= mod;
		}
	}
	return solve();
}

int init(int N, int X[], int Y[]) {
	n = N;
	C.resize(n);
	P.resize(n);
	for(int i = 0; i < n; ++i) C[i] = X[i];
	for(int i = 0; i < n; ++i) P[i] = Y[i];
	memset(treeProd, 1, sizeof(P));
	memset(treeMax, 0, sizeof(P));
	for(int i = 0; i < n; ++i) {
		updateProd(0, n - 1, i, 0, C[i]);
		updateMax(0, n - 1, i, 0, P[i]);
	}

	for(int i = 0; i < n; ++i)
		if(C[i] != 1) _indices.insert(i), _negindices.insert(-i);

	return solve();
}

int updateX2(int pos, int val) {
	if(n > 1000 && pos < n - 100) {
		preprod *= inv(C[pos]);
		preprod %= mod;
		preprod *= (ll)val;
		preprod %= mod;
	}
	C[pos] = val;
	return solve();
}

int updateX(int pos, int val) {
	updateProd(0, n-1, pos, 0, val);
	if(C[pos] == 1 && val != 1) _indices.insert(pos), _negindices.insert(-pos);
	if(C[pos] != 1 && val == 1) _indices.erase(pos), _negindices.erase(-pos);
	C[pos] = val;
	return solve();
}

int updateY2(int pos, int val) {
	P[pos] = val;
	return solve();
}

int updateY(int pos, int val) {
	updateMax(0, n-1, pos, 0, val);
	P[pos] = val;
	return solve();
}

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