Problem:
Score : 700 points

Problem Statement

N hotels are located on a straight line. The coordinate of the i-th hotel (1 \leq i \leq N) is x_i.

Tak the traveler has the following two personal principles:

He never travels a distance of more than L in a single day.

He never sleeps in the open. That is, he must stay at a hotel at the end of a day.

You are given Q queries. The j-th (1 \leq j \leq Q) query is described by two distinct integers a_j and b_j.
For each query, find the minimum number of days that Tak needs to travel from the a_j-th hotel to the b_j-th hotel following his principles.
It is guaranteed that he can always travel from the a_j-th hotel to the b_j-th hotel, in any given input.

Constraints

2 \leq N \leq 10^5

1 \leq L \leq 10^9

1 \leq Q \leq 10^5

1 \leq x_i < x_2 < ... < x_N \leq 10^9

x_{i+1} - x_i \leq L

1 \leq a_j,b_j \leq N

a_j \neq b_j

N,\,L,\,Q,\,x_i,\,a_j,\,b_j are integers.

Partial Score

200 points will be awarded for passing the test set satisfying N \leq 10^3 and Q \leq 10^3.

Input

The input is given from Standard Input in the following format:

N
x_1 x_2 ... x_N
L
Q
a_1 b_1
a_2 b_2
:
a_Q b_Q

Output

Print Q lines.
The j-th line (1 \leq j \leq Q) should contain the minimum number of days that Tak needs to travel from the a_j-th hotel to the b_j-th hotel.

Sample Input 1

9
1 3 6 13 15 18 19 29 31
10
4
1 8
7 3
6 7
8 5

Sample Output 1

4
2
1
2

For the 1-st query, he can travel from the 1-st hotel to the 8-th hotel in 4 days, as follows:

Day 1: Travel from the 1-st hotel to the 2-nd hotel. The distance traveled is 2.

Day 2: Travel from the 2-nd hotel to the 4-th hotel. The distance traveled is 10.

Day 3: Travel from the 4-th hotel to the 7-th hotel. The distance traveled is 6.

Day 4: Travel from the 7-th hotel to the 8-th hotel. The distance traveled is 10.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)


import java.io.*;
import java.util.*;
 
public class Main{
	class Query{
		int idx;
		int a;
		int b;
		public Query(int idx, int a, int b){
			this.idx = idx;
			this.a = a;
			this.b = b;
		}
	}
	
	int N;
	int[] X;
	int L;
	int Q;
	Query[] AB;
	int[][] Xn;
	public void solve(){
		N = nextInt();
		X = new int[N];
		for(int i = 0; i < N; i++){
			X[i] = nextInt();
		}
		L = nextInt();
		Q = nextInt();
		AB = new Query[Q];
		for(int i = 0; i < Q; i++){
			int a = nextInt() - 1;
			int b = nextInt() - 1;
			
			AB[i] = new Query(i, Math.min(a, b), Math.max(a, b));
		}
		

		Xn = new int[N][15];
		int nn = 0;
		for(int i = 0; i < N; i++){
			while(nn < N && X[nn] - X[i] <= L) nn++;
			Xn[i][0] = nn - 1;
		}
		for(int d = 1; d < Xn[0].length; d++){
			for(int i = 0; i < N; i++){
				Xn[i][d] = Xn[Xn[i][d - 1]][d - 1];
			}
		}
		
		for(int i = 0; i < Q; i++){
			int ans = 0;
			out.println(count(AB[i].a, AB[i].b));
		}
	}
	
	public int count(int a, int b){
		if(a == b){
			return 0;
		}
		if(Xn[a][0] >= b){
			return 1;
		}
		int base = 1;
		for(int d = 1; d < Xn[a].length; d++){
			if(Xn[a][d] >= b){
				return base + count(Xn[a][d-1], b);
			}
			base *= 2;
		}
		throw new RuntimeException();
	}
	
	public long f(long b, long n){
		if(n < b){
			return n;
		}else{
			return f(b, n / b) + n % b;
		}
	}
	
	
	
	private static PrintWriter out;
	public static void main(String[] args){
		out = new PrintWriter(System.out);
		new Main().solve();
		out.flush();
	}
	
	
	
	public static int nextInt(){
		int num = 0;
		String str = next();
		boolean minus = false;
		int i = 0;
		if(str.charAt(0) == '-'){
			minus = true;
			i++;
		}
		int len = str.length();
		for(;i < len; i++){
			char c = str.charAt(i);
			if(!('0' <= c && c <= '9')) throw new RuntimeException();
			num = num * 10 + (c - '0');
		}
		return minus ? -num : num;
	}
	
	public static long nextLong(){
		long num = 0;
		String str = next();
		boolean minus = false;
		int i = 0;
		if(str.charAt(0) == '-'){
			minus = true;
			i++;
		}
		int len = str.length();
		for(;i < len; i++){
			char c = str.charAt(i);
			if(!('0' <= c && c <= '9')) throw new RuntimeException();
			num = num * 10l + (c - '0');
		}
		return minus ? -num : num;
	}
	public static String next(){
		int c;
		while(!isAlNum(c = read())){}
		StringBuilder build = new StringBuilder();
		build.append((char)c);
		while(isAlNum(c = read())){
			build.append((char)c);
		}
		return build.toString();
	}
	
	
	private static byte[] inputBuffer = new byte[1024];
	private static int bufferLength = 0;
	private static int bufferIndex = 0;
	private static int read(){
		if(bufferLength < 0) throw new RuntimeException();
		if(bufferIndex >= bufferLength){
			try{
				bufferLength = System.in.read(inputBuffer);
				bufferIndex = 0;
			}catch(IOException e){
				throw new RuntimeException(e);
			}
			if(bufferLength <= 0) return (bufferLength = -1);
		}
		return inputBuffer[bufferIndex++];
	}
	
	private static boolean isAlNum(int c){
		return '!' <= c && c <= '~';
	}
}