acm ----枚举 ----problem 5

fuck。。。。打错一个变量名害我在这题上用了n长时间，我就搞不懂了。。怎么debug都不会么？？？？！！！！！

tmd。。。好好分析这种题目。。然后做一篇关于debug的总结。

holy shit！！！

 

#include <cstdlib>
#include <iostream>

/**
*     PROBLEM 5    讨厌的青蛙 
*/
using namespace std;

/**
*   this struct is used to store trampled rice
*------------------------------------------------
*   enumerate each pair of points in all points 
*/
struct Plant
{
       int x;
       int y;
};
int r,c,n;
Plant plants[5001];
int searchpath(Plant select,int dx,int dy);
int cmp(const void *ele1, const void *ele2);
int main(int argc, char *argv[])
{

    int dX, dY;
    int pX, pY;
    int steps;
    int max;
    max=2;
    scanf("%d%d",&r,&c);
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    {
            scanf("%d%d",&plants[i].x,&plants[i].y);
    }
    qsort(plants,n,sizeof(Plant),cmp);//  STL sort the input  ascending order
    for(int i=0;i<n-2;i++)    //at least 3 point in a line, so maximum i is n-3
    {        
             for(int j=i+1;j<n-1;j++)
            {
                     //plant[i] is the starting point within the matrix
                     cout<<plants[i].x<<plants[i].y<<endl;                    
                     dX=plants[j].x-plants[i].x;
                     dY=plants[j].y-plants[i].y;    //!!!!!!!fuck!!!!!!!!!mlgb的写错了。。
                     pX=plants[i].x-dX;// the frog's starting point is out of border
                     pY=plants[i].y-dY;    
                     if(pX<=r&&pX>=1&&pY>=1&&pY<=c)//if the frog's starting point is NOT out 
                     {        continue;       }     //of border, then continue
                     if(plants[i].x+dX*max>r)
                      {       break;          }
                     pY=plants[i].y+dY*max;
                     if(pY>c||pY<1)
                     {        continue;       }
                     steps=searchpath(plants[j],dX,dY); //after "steps", overstep the border
                     if(steps>max)
                     {        max=steps;      }              
            }
    }
    if(max==2) max=0;
    printf("%d\n",max);
    
    system("PAUSE");
    return EXIT_SUCCESS;
}
int cmp(const void *ele1, const void *ele2)  //comparision function
{
    Plant *p1, *p2;
    p1=(Plant *)ele1;
    p2=(Plant *)ele2;
    if(p1->x==p2->x)  return (p1->y-p2->y);
    return (p1->x-p2->x);
}
int searchpath(Plant select,int dx,int dy)
{
    Plant plant;
    int step;
    step=2;
    plant.x=select.x+dx;
    plant.y=select.y+dy;
    while(plant.x<=r&&plant.x>=1&&plant.y<=c&&plant.y>=1)
    {
          if(!bsearch(&plant,plants,n,sizeof(Plant),cmp))//binary search STL, find the plant  
          {
                  step=0;    //the path is not available
                  break;   
          }
          plant.x+=dx;
          plant.y+=dy;
          step++;
    }

    return step;
}

杯具啊。。。我真是差好多好多。。就这现在这鸟样就别说自己是学计算机的了。。