如何基于Y轴对点矢量进行排序？

Question

我有一组坐标,例如:

10,40; 9,27; 5.68; 7.55; 8,15;

如何在不丢失已排序Y轴的正确X轴的情况下对这些坐标进行排序.

从上面的例子我想要排序坐标,所以正确的输出将是:

8,15; 9,27; 10,40; 7.55; 5.68.

任何建议将不胜感激.谢谢.

Answer 1

std :: sort的文档

#include "opencv2/core/core.hpp"
#include <algorithm>    // std::sort

// This defines a binary predicate that, 
// taking two values of the same type of those 
// contained in the list, returns true if the first 
// argument goes before the second argument
struct myclass {
    bool operator() (cv::Point pt1, cv::Point pt2) { return (pt1.y < pt2.y);}
} myobject;

int main () {
    // input data
    std::vector<cv::Point> pts(5);
    pts[0] = Point(10,40);
    pts[1] = Point(9,27);
    pts[2] = Point(5,68);
    pts[3] = Point(7,55);
    pts[4] = Point(8,15);

    // sort vector using myobject as comparator
    std::sort(pts.begin(), pts.end(), myobject);
}