Submission #560147

#	Time	Username	Problem	Language	Result	Execution time	Memory
560147		amunduzbaev	Sparklers (JOI17_sparklers)	C++17	100 / 100	445 ms	7868 KiB

sparklers

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

#define ar array
#define int long long

const int inf = 1e9 + 5;

const int N = 1e5 + 5;

struct ST{
	int mn[N<<2], mx[N<<2];
	
	void sett(int i, int v, int lx = 0, int rx = N, int x = 1){
		if(lx == rx) { mn[x] = mx[x] = v; return; }
		int m = (lx + rx) >> 1;
		if(i <= m) sett(i, v, lx, m, x<<1);
		else sett(i, v, m+1, rx, x<<1|1);
		mn[x] = min(mn[x<<1], mn[x<<1|1]);
		mx[x] = max(mx[x<<1], mx[x<<1|1]);
	}
	
	int get_rm_low(int l, int r, int v, int lx = 0, int rx = N, int x = 1){
		if(lx > r || rx < l) return -1;
		if(lx >= l && rx <= r){
			if(mn[x] > v) return -1;
			if(lx == rx) return lx;
			int m = (lx + rx) >> 1;
			if(mn[x<<1|1] <= v) return get_rm_low(l, r, v, m+1, rx, x<<1|1);
			return get_rm_low(l, r, v, lx, m, x<<1);
		} int m = (lx + rx) >> 1;
		int res = get_rm_low(l, r, v, m+1, rx, x<<1|1);
		if(~res) return res;
		return get_rm_low(l, r, v, lx, m, x<<1);
	}
	
	int get_lm_big(int l, int r, int v, int lx = 0, int rx = N, int x = 1){
		if(lx > r || rx < l) return -1;
		if(lx >= l && rx <= r){
			if(mx[x] < v) return -1;
			if(lx == rx) return lx;
			int m = (lx + rx) >> 1;
			if(mx[x<<1] >= v) return get_lm_big(l, r, v, lx, m, x<<1);
			return get_lm_big(l, r, v, m+1, rx, x<<1|1);
		} int m = (lx + rx) >> 1;
		int res = get_lm_big(l, r, v, lx, m, x<<1);
		if(~res) return res;
		return get_lm_big(l, r, v, m+1, rx, x<<1|1);
	}
}tree;

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n, k, t; cin>>n>>k>>t;
	
	vector<int> a(n), d(n);
	for(int i=0;i<n;i++) cin>>a[i], a[i] *= 2;
	for(int i=1;i<n;i++){
		d[i] = a[i] - a[i-1];
	}
	k--;
	
	auto check = [&](int s){
		vector<int> b(n);
		for(int i=0;i<n;i++) b[i] = a[i] / 2 - i * s * t, tree.sett(i, b[i]);
		int pos = tree.get_lm_big(k, n-1, b[k] + 1);
		if(pos == -1) pos = n;
		pos--;
		for(int i=k;i>0;i--){
			if(b[i-1] >= b[i]){
				pos = tree.get_lm_big(pos, n-1, b[i-1] + 1);
				if(pos == -1) pos = n;
				pos--;
			} else {
				pos = tree.get_rm_low(k, pos, b[i-1]);
				if(pos == -1){
					return false;
				}
			}
		}
		
		return (pos == n - 1);
	};
	
	int l = 0, r = 2 * inf;
	while(l < r){
		int m = (l + r) >> 1;
		if(check(m)) r = m;
		else l = m + 1;
	}
	
	cout<<(l+1) / 2<<"\n";
}

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 50 / 50