1 //2017-04-06
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <algorithm>
 6 
 7 using namespace std;
 8 
 9 const int inf = 0x3f3f3f3f;
10 struct node{
11     int l, r, h;
12     bool operator<(const node x)
13     {
14         return this->h > x.h;
15     }
16 }platform[1005];
17 int dpl[1005], dpr[1005];//dpl[i]记录从第i块平台左端点落地所需的最短时间,dpr[i]记录从第i块平台右端点落地所需的最短时间
18 int n, MAX;
19 
20 int dfs(int x, int y, int ptr)//输入参数表示从第ptr块平台，位于(x, y)点开始搜索
21 {
22     if(dpl[ptr] != inf && dpr[ptr] != inf)
23       if(y-platform[ptr].h <= MAX)
24         if(platform[ptr].l <= x && platform[ptr].r >= x)
25           return y-platform[ptr].h+min(dpl[ptr]+x-platform[ptr].l, dpr[ptr]+platform[ptr].r-x);//记忆化搜索，返回位于(x, y)点向左右走的最短时间
26     int l, r, h;
27     for(int i = ptr; i < n; i++){
28         l = platform[i].l;
29         r = platform[i].r;
30         h = platform[i].h;
31         if(h <= y && y-h <= MAX){
32             if(x >= l && x <= r){
33                 if(h == 0)return y-h;
34                 else{
35                     int left = dfs(l, h, i+1);//向左走
36                     dpl[i] = min(dpl[i], left);
37                     int right = dfs(r, h, i+1);//向右走
38                     dpr[i] = min(dpr[i], right);
39                     return y-h+min(dpl[i]+x-l, dpr[i]+r-x);
40                 }
41             }
42         }
43     }
44     return inf;
45 }
46 
47 int main()
48 {
49     int T, x, y, ans;
50     scanf("%d", &T);
51     while(T--)
52     {
53         scanf("%d%d%d%d", &n, &x, &y, &MAX);        
54         for(int i = 0; i < n; i++){
55             scanf("%d%d%d", &platform[i].l, &platform[i].r, &platform[i].h);
56             dpl[i] = dpr[i] = inf;
57         }
58         //加入地面这一块平台，高度为0，左右边界无穷
59         platform[n].h = 0;
60         platform[n].l = -inf;
61         platform[n].r = inf;
62         dpl[n] = dpr[n] = inf;
63         n++;
64         sort(platform, platform+n);
65         int l, r, h, i;
66         for(i = 0; i < n; i++)//找到下落遇到的地一块平台，从这块平台开始搜索
67         {
68             l = platform[i].l;
69             r = platform[i].r;
70             h = platform[i].h;
71             if(h <= y && y-h <= MAX)
72               if(x >= l && x <= r)
73                 break;    
74         }
75         ans = dfs(x, h, i)+y-h;
76         printf("%d\n", ans);
77     }
78 
79     return 0;
80 }