c++ - 删除重复项而不四舍五入，C++

Question

我正在尝试使用以下比较器从 vector 中删除重复项

            bool operator() ( const Point * p1, const Point * p2 ) const
            {
                    return ( p1->X() < p2->X() ) || ( ( p1->X() == p2->X() ) && ( p1->Y() < p2-Y() ) );
            }

和重载的运算符==

bool Point::operator == ( const Point &p ) const
{
    return ( x - p.x ) * ( x - p.x ) + ( y - p.y ) * ( y - p.y ) < DIFF;
}

原理图去除:

std::sort ( it_begin, it_end, Comp );
Points::iterator i_new_end = std::unique ( it_begin, it_end, Uniq);
items.erase ( i_new_end, this->items.end() );

但是数据有问题。根据x坐标排序的点

-0.0000000015   -6281103.8487118632   0.0000000000
-0.0000000011   -5993359.5353725236   0.0000000000
-0.0000000010   -5523510.0253371494   0.0000000000
-0.0000000009   -4885831.4582128422   0.0000000000
-0.0000000009   -4099699.3745807474   0.0000000000
-0.0000000008   -3189000.0000000000   0.0000000000
-0.0000000008   -2181404.4741311157   0.0000000000
-0.0000000008   -1107528.0771596823   0.0000000000 //unique
-0.0000000008   -0.0000000005   0.0000000000
-0.0000000007   1107528.0771596811   0.0000000000  //unique
-0.0000000007   2181404.4741311143   0.0000000000
-0.0000000007   3188999.9999999991   0.0000000000
-0.0000000006   4099699.3745807474   0.0000000000
-0.0000000006   4885831.4582128404   0.0000000000
-0.0000000005   5523510.0253371485   0.0000000000
-0.0000000004   5993359.5353725236   0.0000000000
0.0000000000   -6281103.8487118632   0.0000000000
0.0000000004   5993359.5353725236   0.0000000000
0.0000000005   5523510.0253371485   0.0000000000
0.0000000006   4099699.3745807474   0.0000000000
0.0000000006   4885831.4582128404   0.0000000000
0.0000000007   1107528.0771596811   0.0000000000
0.0000000007   2181404.4741311143   0.0000000000
0.0000000007   3188999.9999999991   0.0000000000
0.0000000008   -3189000.0000000000   0.0000000000
0.0000000008   -2181404.4741311157   0.0000000000
0.0000000008   -1107528.0771596823   0.0000000000
0.0000000008   -0.0000000005   0.0000000000
0.0000000009   -4885831.4582128422   0.0000000000
0.0000000009   -4099699.3745807474   0.0000000000
0.0000000010   -5523510.0253371494   0.0000000000
0.0000000011   -5993359.5353725236   0.0000000000
0.0000000015   -6281103.8487118632   0.0000000000
0.0089638987   -6377999.9999999991   0.0000000000

运算符 == 不会带来任何影响，附近的点不会彼此相邻排序...

是否有可能在不四舍五入的情况下删除此类重复点(例如 diffrenet 比较器)？我知道，坐标有很多小数位...

Answer 1

std::sort 需要运算符 <，而不是运算符 ==