POJ 1661 DP 注意邊界條件。。。WA了好幾次

//
//  main.cpp
//  POJ 1661 DP
//
//  Created by 鄭喆君 on 8/12/14.
//  Copyright (c) 2014 itcast. All rights reserved.
//

#include<cstdio>
#include<cstring>
#include<iostream>
#include<iomanip>
#include<queue>
#include<cmath>
#include<stack>
#include<map>
#include<vector>
#include<set>
#include<algorithm>
using namespace std;
typedef long long LL;
const int int_max = 0x07777777;
const int int_min = 0x80000000;
struct Node {
    int x,y,h;
    //Node(int _x, int _y, int _h):x(_x),y(_y),h(_h){}
};
int cmp (const void* a, const void* b){
    return ((Node*)b)->h - ((Node*)a)->h;
}
int N,X,Y,MAXH;
Node nodes[1100];
int dp[1100][2];
int main(int argc, const char * argv[])
{
    int t;
    scanf("%d", &t);
    while (t--) {
        scanf("%d %d %d %d", &N, &X, &Y, &MAXH);
        for(int i = 0; i < N; i++){
            int x,y,h;
            scanf("%d %d %d", &x, &y, &h);
            Node temp;
            temp.x = x;
            temp.y = y;
            temp.h = h;
            nodes[i] = temp;
        }
        qsort(nodes, N, sizeof(nodes[0]), cmp);
        memset(dp, -1, sizeof(dp));
        int starti = -1;
        for(int i = 0; i < N; i++){
            if(Y-nodes[i].h<=MAXH && X>=nodes[i].x && X<=nodes[i].y){
                starti = i;
                dp[i][0] = Y-nodes[i].h + X-nodes[i].x;
                dp[i][1] = Y-nodes[i].h + nodes[i].y-X;
                break;
            }
        }
        if(starti==-1){
            printf("%d\n", Y);
            continue;
        }
        for(int i = starti; i < N; i++){
            if(dp[i][0]==-1) continue;
            for(int j = i+1; j < N; j++){
                if(nodes[i].h-nodes[j].h > MAXH) break;
                if(nodes[i].x>=nodes[j].x && nodes[i].x<=nodes[j].y){
                    int xx = nodes[i].h-nodes[j].h + nodes[i].x-nodes[j].x;
                    int yy = nodes[i].h-nodes[j].h + nodes[j].y-nodes[i].x;
                    if(dp[j][0]==-1 || dp[j][0]>dp[i][0]+xx) dp[j][0] = dp[i][0]+xx;
                    if(dp[j][1]==-1 || dp[j][1]>dp[i][0]+yy) dp[j][1] = dp[i][0]+yy;
                    break;
                }
            }
            for(int j = i+1; j < N; j++){
                if(nodes[i].h-nodes[j].h > MAXH) break;
                if(nodes[i].y>=nodes[j].x && nodes[i].y<=nodes[j].y){
                    int xx = nodes[i].h-nodes[j].h + nodes[i].y-nodes[j].x;
                    int yy = nodes[i].h-nodes[j].h + nodes[j].y-nodes[i].y;
                    if(dp[j][0]==-1 || dp[j][0]>dp[i][1]+xx) dp[j][0] = dp[i][1]+xx;
                    if(dp[j][1]==-1 || dp[j][1]>dp[i][1]+yy) dp[j][1] = dp[i][1]+yy;
                    break;
                }
            }
        }
        int result = int_max;
        for(int i = N-1; i >= 0; i--){
            if(dp[i][0]==-1) continue;
            if(nodes[i].h > MAXH) break;
            int j;
            for(j = i+1; j < N; j++){
                if(nodes[i].h-nodes[j].h<=MAXH && ((nodes[i].x>=nodes[j].x&&nodes[i].x<=nodes[j].y)))
                    break;
            }
            if(j==N) result = (result > dp[i][0]+nodes[i].h ? dp[i][0]+nodes[i].h : result);
        }
        for(int i = N-1; i >= 0; i--){
            if(dp[i][0]==-1) continue;
            if(nodes[i].h > MAXH) break;
            int j;
            for(j = i+1; j < N; j++){
                if(nodes[i].h-nodes[j].h<=MAXH && ((nodes[i].y>=nodes[j].x&&nodes[i].y<=nodes[j].y)))
                    break;
            }
            if(j==N) result = (result > dp[i][1]+nodes[i].h ? dp[i][1]+nodes[i].h : result);
        }
        printf("%d\n",result);
    }
}