#include #include #define MAXN 1010 #define INF 9000000 typedef struct platform{ int x1; int x2; int high; }Platform; int compare (const void * p, const void * q){ Platform * p1 = (Platform *)p; Platform * q1 = (Platform *)q; return p1->high - q1->high; } int Min (int a, int b){ return (a < b) ? a : b; } int N, X, Y, MAX; Platform plat[MAXN]; int dp[MAXN][2]; //dp[i][0]、dp[i][1]分别表示从第i个平台左、右边到地面的最短时间 void LeftMinTime (int i){ //计算从平台i左边到地面的最短时间 int k = i - 1; while (k > 0 && plat[i].high - plat[k].high <= MAX){ //如果平台i左边下面有平台,且两者相距不超过MAX if (plat[i].x1 >= plat[k].x1 && plat[i].x1 <= plat[k].x2){ dp[i][0] = plat[i].high - plat[k].high + Min (plat[i].x1 - plat[k].x1 + dp[k][0], plat[k].x2 - plat[i].x1 + dp[k][1]); return; } else --k; } //如果平台i左边下面没有平台,或者两者相距超过了MAX if (plat[i].high - plat[k].high > MAX) dp[i][0] = INF; else dp[i][0] = plat[i].high; } void RightMinTime (int i){ //计算从平台i右边到地面的最短时间 int k = i - 1; while (k > 0 && plat[i].high - plat[k].high <= MAX){ //如果平台i右边下面有平台,且两者相距不超过MAX if (plat[i].x2 >= plat[k].x1 && plat[i].x2 <= plat[k].x2){ dp[i][1] = plat[i].high - plat[k].high + Min (plat[i].x2 - plat[k].x1 + dp[k][0], plat[k].x2 - plat[i].x2 + dp[k][1]); return; } else --k; } //如果平台i右边下面没有平台,或者两者相距超过了MAX if (plat[i].high - plat[k].high > MAX) dp[i][1] = INF; else dp[i][1] = plat[i].high; } int ShortestTime (){ int i, j; for (i=1; i<=N+1; ++i){ LeftMinTime (i); RightMinTime (i); } return Min (dp[N+1][0], dp[N+1][1]); } int main(void){ int t; int i; while (scanf ("%d", &t) != EOF){ while (t-- != 0){ scanf ("%d%d%d%d", &N, &X, &Y, &MAX); for (i=1; i<=N; ++i){ scanf ("%d%d%d", &plat[i].x1, &plat[i].x2, &plat[i].high); } plat[0].high = 0; plat[0].x1 = -20000; plat[0].x2 = 20000; plat[N+1].high = Y; plat[N+1].x1 = X; plat[N+1].x2 = X; //根据平台高度按从低到高排序 qsort (plat, N+2, sizeof(Platform), compare); printf ("%d\n", ShortestTime()); } } return 0; }