https://codeforces.com/contest/1082/problem/A
题解:
一共四种情况
1、往左走没有到n就达到目的地(包括目的地为n)
2、往右走没有到1就达到目的地(包括目的地为1)
3、往左走到n,回头再达到目的地
4、往右走到1,回头再达到目的地
/*
*@Author: STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
using namespace std;
typedef long long ll;
const int N=10000;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const ll INF = 0x3f3f3f3f3f3f3f;
int t;
ll n,x,y,d,m;
int main()
{
#ifdef DEBUG
freopen("input.in", "r", stdin);
//freopen("output.out", "w", stdout);
#endif
scanf("%d",&t);
while(t--){
scanf("%I64d%I64d%I64d%I64d",&n,&x,&y,&d);
if(labs(x-y)%d==0){
cout << labs(x-y)/d << endl;
}else{
int l=(x-1)/d;
if((x-1)%d)l++;
int r=(n-x)/d;
if((n-x)%d)r++;
ll ans=INF;
if((y-1)%d==0){
ans=min(ans,l+(y-1)/d);
}
if((n-y)%d==0){
ans=min(ans,r+(n-y)/d);
}
if(ans!=INF){
cout << ans << endl;
}else{
cout << -1 << endl;
}
}
}
//cout << "Hello world!" << endl;
return 0;
}