POJ 1661 Help Jimmy

#include<cstdio>
#include<cstring>
#include<cmath>
#include<stack>
#include<vector>
#include<string>
#include<iostream>
#include<algorithm>
using namespace std;

const int maxn=1000+10;
int T;
int N,X,Y,MAX;
struct W
{
int x1,x2,h;
} s[maxn];
int dpLeft[maxn],dpRight[maxn];

bool cmp(const W&a,const W&b)
{
return a.h>b.h;
}

int main()
{
scanf("%d",&T);
while(T--)
{
scanf("%d%d%d%d",&N,&X,&Y,&MAX);
s[0].x1=X,s[0].x2=X,s[0].h=Y;
for(int i=1; i<=N; i++) scanf("%d%d%d",&s[i].x1,&s[i].x2,&s[i].h);
s[N+1].x1=-0x7fffffff,s[N+1].x2=0x7FFFFFFF,s[N+1].h=0;

for(int i=0; i<=N+1; i++) dpRight[i]=dpLeft[i]=0x7fffffff;
sort(s+1,s+N+1,cmp);

dpLeft[0]=0,dpRight[0]=0;
int ans=0x7FFFFFFF;
for(int i=0; i<=N; i++)
{
//从左端下落
if(dpLeft[i]!=0x7fffffff)
{
for(int j=i+1; j<=N+1; j++)
{
if(s[j].x1<=s[i].x1&&s[i].x1<=s[j].x2)
{
if(s[i].h-s[j].h<=MAX)
{
if(j==N+1)
{
int cost=dpLeft[i]+s[i].h-s[j].h;
ans=min(ans,cost);
}
else
{
int cost;
//到左端需要的时间
cost=dpLeft[i]+s[i].h-s[j].h+s[i].x1-s[j].x1;
dpLeft[j]=min(cost,dpLeft[j]);

//到右端需要的时间
cost=dpLeft[i]+s[i].h-s[j].h+s[j].x2-s[i].x1;
dpRight[j]=min(cost,dpRight[j]);
}
}
break;
}
}
}
//往右跑
if(dpRight[i]!=0x7fffffff)
{
for(int j=i+1; j<=N+1; j++)
{
if(s[j].x1<=s[i].x2&&s[i].x2<=s[j].x2)
{
if(s[i].h-s[j].h<=MAX)
{
if(j==N+1)
{
int cost=dpRight[i]+s[i].h-s[j].h;
ans=min(ans,cost);
}
else
{
int cost;
//到左端需要的时间
cost=dpRight[i]+s[i].h-s[j].h+s[i].x2-s[j].x1;
dpLeft[j]=min(cost,dpLeft[j]);

//到右端需要的时间
cost=dpRight[i]+s[i].h-s[j].h+s[j].x2-s[i].x2;
dpRight[j]=min(cost,dpRight[j]);
}
}
break;
}
}
}
}
printf("%d\n",ans);
}
return 0;
}