poj2318

简单题，二分查找

View Code

   
     

    
      #include 
    
      <
    
      iostream
    
      >
    
      
#include 
    
      <
    
      cstdio
    
      >
    
      
#include 
    
      <
    
      cstdlib
    
      >
    
      
#include 
    
      <
    
      cstring
    
      >
    
      
#include 
    
      <
    
      algorithm
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;


    
      #define
    
       maxn 5005
    
      


    
      struct
    
       Line
{
 
    
      int
    
       u, d;
} line[maxn];


    
      int
    
       n, m, x1, x2, y1, y2;

    
      int
    
       toy[maxn];


    
      bool
    
       left(
    
      int
    
       x, 
    
      int
    
       y, Line a)
{
 
    
      if
    
       (x 
    
      <
    
       a.d 
    
      +
    
       (y 
    
      -
    
       y2) 
    
      *
    
       (a.u 
    
      -
    
       a.d) 
    
      *
    
       
    
      1.0
    
       
    
      /
    
       (y1 
    
      -
    
       y2))
 
    
      return
    
       
    
      true
    
      ;
 
    
      return
    
       
    
      false
    
      ;
}


    
      int
    
       binarysearch(
    
      int
    
       x, 
    
      int
    
       y)
{
 
    
      int
    
       l 
    
      =
    
       
    
      0
    
      , r 
    
      =
    
       n;
 
    
      int
    
       mid;

 
    
      while
    
       (l 
    
      <
    
       r)
 {
 mid 
    
      =
    
       (l 
    
      +
    
       r) 
    
      /
    
       
    
      2
    
      ;
 
    
      if
    
       (left(x, y, line[mid]))
 r 
    
      =
    
       mid;
 
    
      else
    
      
 l 
    
      =
    
       mid 
    
      +
    
       
    
      1
    
      ;
 }
 
    
      return
    
       l;
}


    
      int
    
       main()
{
 
    
      //
    
      freopen("t.txt", "r", stdin);
    
      

    
       
    
      while
    
       (scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n), n 
    
      !=
    
       
    
      0
    
      )
 {
 memset(toy, 
    
      0
    
      , 
    
      sizeof
    
      (toy));
 scanf(
    
      "
    
      %d%d%d%d%d
    
      "
    
      , 
    
      &
    
      m, 
    
      &
    
      x1, 
    
      &
    
      y1, 
    
      &
    
      x2, 
    
      &
    
      y2);
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       n; i
    
      ++
    
      )
 scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      line[i].u, 
    
      &
    
      line[i].d);
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       m; i
    
      ++
    
      )
 {
 
    
      int
    
       x, y;
 scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      x, 
    
      &
    
      y);
 toy[binarysearch(x, y)]
    
      ++
    
      ;
 }
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <=
    
       n; i
    
      ++
    
      )
 printf(
    
      "
    
      %d: %d\n
    
      "
    
      , i, toy[i]);
 printf(
    
      "
    
      \n
    
      "
    
      );
 }
 
    
      return
    
       
    
      0
    
      ;
}