Help Jimmy

http://poj.org/problem?id=1661

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define MAX_N 1000
#define INFINITE 1000000
int t, n, x, y, max_h;

struct Platform{
     int Lx, Rx, h;
     bool operator < (const Platform& b) const
     {  
         return h > b.h;
     }   
};
//int MyCompare( const void * e1, const void * e2 )
//{
//    Platform * p1, * p2;
//    p1 = (Platform * ) e1;
//    p2 = (Platform * ) e2;
//    return p2->h - p1->h;
//}
Platform aPlatform[MAX_N + 10];
int aLeftMinTime[MAX_N + 10];
int aRightMinTime[MAX_N + 10];

/*
1
3 8 17 20
0 10 8
0 10 13
4 14 3

*/
int MinTime(int L, bool left)
{
     int y = aPlatform[L].h;
     int x;
    
     if(left)
         x=aPlatform[L].Lx;
     else
         x=aPlatform[L].Rx;
     //检查是否L底下有平台
     int j=-1;
     for(int i=L+1;i<=n;i++)
     {
         if(aPlatform[i].Lx<=x && x<=aPlatform[i].Rx )
         {
             j=i;
             break;   
         }   
     }

    if(j==-1)//底下没平台
         if(y > max_h)
             return INFINITE;
         else
             return y;
     // 有平台的情况
     // 1、如果高度超过
     if(aPlatform[L].h - aPlatform[j].h > max_h)
         return  INFINITE;
     // 2、没超过，就计算左边的时间和右边的时间，取两者中最短的
    
    
     int hTime=aPlatform[L].h - aPlatform[j].h;//下落时间
     int leftTime=x-aPlatform[j].Lx;//向左走的时间
     int rightTime=aPlatform[j].Rx-x;//向右走的时间
     if(aLeftMinTime[j]==-1)
         aLeftMinTime[j]=MinTime(j, true);
     if(aRightMinTime[j]==-1)
         aRightMinTime[j]=MinTime(j, false);
     if(leftTime+aLeftMinTime[j]<rightTime+aRightMinTime[j])
         return hTime+leftTime+aLeftMinTime[j];//下落+向左+下层向左掉落
     else
         return hTime+rightTime+aRightMinTime[j];
}

int main()
{
     scanf("%d", &t);
     for( int i = 0;i < t; i ++ ) {
         memset(aLeftMinTime, -1, sizeof(aLeftMinTime));
         memset(aRightMinTime, -1, sizeof(aRightMinTime));
         scanf("%d%d%d%d", &n, &x, &y, &max_h);
         aPlatform[0].Lx=aPlatform[0].Rx=x;
         aPlatform[0].h =y;
         for(int j=1;j<=n;j++)
             scanf("%d%d%d", & aPlatform[j].Lx, & aPlatform[j].Rx, & aPlatform[j].h);
         sort(aPlatform, aPlatform+n+1);
//        qsort(aPlatform, n+1, sizeof(Platform), MyCompare);
//        for(int i=0;i<=n;i++)
//        {
//            printf("%d %d %d ",  aPlatform[i].Lx,  aPlatform[i].Rx, aPlatform[i].h);
//        }
         printf("%d ", MinTime(0, true));
     }

    return 0;
}

递推方式

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <algorithm>

using namespace std;

#define MAX_N 1000

#define INFINITE 1000000

int t, n, x, y, MAX;

struct Platform{

    int Lx, Rx, h;

    //根据h从小到大排列

    bool operator <(const Platform& r) const

    {

        return h<r.h;

    }

} ;

Platform aPlatform[MAX_N + 10];

int aLeftMinTime[MAX_N + 10];

int aRightMinTime[MAX_N + 10];

int main()

{

    scanf("%d", &t);

    for( int i = 0;i < t; i ++ ) {

        memset(aLeftMinTime, 0x3f, sizeof(aLeftMinTime));

        memset(aRightMinTime, 0x3f, sizeof(aRightMinTime));

        scanf("%d%d%d%d", &n, &x, &y, &MAX);

        aPlatform[n].Lx = x;

        aPlatform[n].Rx = x;

        aPlatform[n].h = y;

        for( int j = 0; j < n; j ++ )

            scanf("%d%d%d", & aPlatform[j].Lx, & aPlatform[j].Rx, & aPlatform[j].h);

        //qsort(aPlatform, n+1, sizeof(Platform), MyCompare);

        sort(aPlatform, aPlatform+n);

        // 最下面的平台开始，从下往上倒推

        for(int j=0;j<=n;j++)

        {

            //分别找左边和右边掉落，碰到的平台编号

            int lp=-1, rp=-1;

            for(int k=j-1;k>=0;k--)

            {

                if(lp==-1 && aPlatform[k].Lx<=aPlatform[j].Lx && aPlatform[k].Rx>=aPlatform[j].Lx)

                {

                    lp=k;

                }

                if(rp==-1 && aPlatform[k].Lx<=aPlatform[j].Rx && aPlatform[k].Rx>=aPlatform[j].Rx)

                {

                    rp=k;

                }

            }

            if(lp==-1 && aPlatform[j].h<=MAX)

                aLeftMinTime[j]=aPlatform[j].h;

            if(rp==-1 && aPlatform[j].h<=MAX)

                aRightMinTime[j]=aPlatform[j].h;

            if(lp!=-1 && (aPlatform[j].h-aPlatform[lp].h)<=MAX)

            {

                aLeftMinTime[j]=aPlatform[j].h-aPlatform[lp].h

                        + min(aPlatform[j].Lx-aPlatform[lp].Lx+aLeftMinTime[lp],aPlatform[lp].Rx-aPlatform[j].Lx+aRightMinTime[lp]);

            }

            if(rp!=-1 && (aPlatform[j].h-aPlatform[rp].h)<=MAX)

            {

                aRightMinTime[j]=aPlatform[j].h-aPlatform[rp].h

                        + min(aPlatform[j].Rx-aPlatform[rp].Lx+aLeftMinTime[rp],aPlatform[rp].Rx-aPlatform[j].Rx+aRightMinTime[rp]);

            }

        }

        printf("%d
", aLeftMinTime[n]);

//        printf("%d
", aRightMinTime[n]);

    }

}

/*

1

4 14 5 6

3 22 1

16 23 2

16 30 3

13 21 4

答案:15

 */