Submission #691267

#	Time	Username	Problem	Language	Result	Execution time	Memory
691267		amunduzbaev	Railway Trip (JOI17_railway_trip)	C++17	20 / 100	2086 ms	11080 KiB

railway_trip

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

#define ar array
typedef long long ll;
//~ #define int ll

const int N = 2e5 + 5;
vector<int> edges[N];
int a[N];

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n, k, q; cin >> n >> k >> q;
	vector<int> ss;
	for(int i=0;i<n;i++){
		cin >> a[i];
		while(!ss.empty() && a[ss.back()] < a[i]){
			//~ edges[ss.back()].push_back(i);
			//~ edges[i].push_back(ss.back());
			ss.pop_back();
		}
		if(!ss.empty()){
			edges[ss.back()].push_back(i);
			edges[i].push_back(ss.back());
		}
		ss.push_back(i);
	}
	ss.clear();
	for(int i=n-1;~i;i--){
		while(!ss.empty() && a[ss.back()] < a[i]){
			//~ edges[ss.back()].push_back(i);
			//~ edges[i].push_back(ss.back());
			ss.pop_back();
		}
		if(!ss.empty()){
			edges[ss.back()].push_back(i);
			edges[i].push_back(ss.back());
		}
		ss.push_back(i);
	}
	int d[n];
	while(q--){
		int a, b; cin >> a >> b; a--, b--;
		memset(d, 63, sizeof d);
		queue<int> q;
		q.push(a); d[a] = 0;
		while(!q.empty()){
			int u = q.front(); q.pop();
			for(auto x : edges[u]){
				if(d[x] > d[u] + 1){
					d[x] = d[u] + 1;
					q.push(x);
				}
			}
		}
		
		cout<<--d[b]<<"\n";
	}
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 25
• Subtask 4: 0 / 55