c++sort对二维数组排序，排序后delete会报错

这是代码

#include<iostream>
using namespace std;
#include<algorithm>
bool cmp(int* a, int* b)
{
	return a[0] < b[0];
}
int main()
{
	int k;
	cin >> k;
	int** a = new int* [k];
	for (int i = 0; i < k; i++) {
		a[i] = new int[2];
		cin >> a[i][0] >> a[i][1];
	}
	sort((int **)a, (int **)(a + k), cmp);
	for (int i = 0; i < k; i++)
		cout << a[i][0] << ' ' << a[i][1] << endl;
	/*for (int i = 0; i < k; k++)
		delete[]a[i];
	delete[]a;*/
	return 0;
}

如果delete的话，会这样

	for (int i = 0; i < k; k++)//i++写成了k++
		delete[]a[i];
	delete[]a;

你这排序算法写的有问题啊，我输入3，{3,1,2,4,5,6}，最后输出{2,4,3,1,5,6,}。你这算法最终实现的效果是按照每个一维数组的[0]位的大小进行排序了。想实现全局的排序得用一块连续的内存才行