HDU 1007 平面最近点对（计算集几何）

http://acm.hdu.edu.cn/showproblem.php pid=1007

我的代码：

#include
  
   
#include
   
     #include
    
      #include
     
       #include
       
       using namespace std
       ; #define size 100000 
       struct pint
       {double x
       , y
       ;} jeo
       [size
       ]; bool cmpx
       (const int &a
       , const int &b
       ){return jeo
       [a
       ].x
        < jeo
       [b
       ].x
       ;} bool cmpy
       (const int &a
       , const int &b
       ){return jeo
       [a
       ].y
        < jeo
       [b
       ].y
       ;} double dis
       (int &a
       , int &b
       ) { return sqrt
       ((jeo
       [a
       ].x
        - jeo
       [b
       ].x
       ) * (jeo
       [a
       ].x
        - jeo
       [b
       ].x
       ) + (jeo
       [a
       ].y
        - jeo
       [b
       ].y
       ) * (jeo
       [a
       ].y
        - jeo
       [b
       ].y
       )); } int n
       , idx
       [size
       ], idy
       [size
       ]; double judge
       (int l
       , int r
       ) { if (r
        - l
        == 1
       ) return dis
       (idx
       [l
       ], idx
       [r
       ]); if (r
        - l
        == 2
       ) return min
       (dis
       (idx
       [l
       ], idx
       [l
        + 1
       ]), min
       (dis
       (idx
       [l
        + 1
       ], idx
       [l
        + 2
       ]), dis
       (idx
       [l
        + 2
       ], idx
       [l
       ]))); int mid
        = (l
        + r
       ) >> 1
       ; double ans
        = min
       (judge
       (l
       , mid
       ), judge
       (mid
        + 1
       , r
       )); int num
        = 0
       ; for(int i
        = l
       ; i
        <= r
       ; i
       ++) if (jeo
       [idx
       [i
       ]].x
        >= jeo
       [idx
       [mid
       ]].x
        - ans
        && jeo
       [idx
       [i
       ]].x
        <= jeo
       [idx
       [mid
       ]].x
        + ans
       ) idy
       [num
       ++] = idx
       [i
       ]; sort
       (idy
       , idy
        + num
       , cmpy
       ); for(int i
        = 0
       ; i
        < num
       ; i
       ++) for(int j
        = i
        + 1
       ; j
        < num
       ; j
       ++) { if (jeo
       [idy
       [j
       ]].y
        - jeo
       [idy
       [i
       ]].y
        >= ans
       ) break; ans
        = min
       (ans
       , dis
       (idy
       [j
       ], idy
       [i
       ])); } return ans
       ; } int main() { while(scanf
       ("%d"
       , &n
       ) && n
       ) { for(int i
        = 0
       ; i
        < n
        && scanf
       ("%lf%lf"
       , &jeo
       [i
       ].x
       , &jeo
       [i
       ].y
       ); i
       ++) idx
       [i
       ] = i
       ; sort
       (idx
       , idx
        + n
       , cmpx
       ); printf
       ("%.2f\n"
       , judge
       (0
       , n
        - 1
       ) * 0.5
       ); } return 0
       ; }