题目:
Given a n x n matrix where each of the rows and columns are sorted in ascending order, find the kth smallest element in the matrix.
Note that it is the kth smallest element in the sorted order, not the kth distinct element.
Example:
matrix = [ [ 1, 5, 9], [10, 11, 13], [12, 13, 15] ], k = 8, return 13.
思路:
建一个大小为k的priority_queue,保存k个最小的元素,算子为less,保证队头元素最大。
程序:
class Solution {
public:
int kthSmallest(vector<vector<int>>& matrix, int k) {
priority_queue<int> ssque;
for (int i = 0; i < k && i < matrix.size(); i++)
{
for (int j = 0; j < k / (i + 1) && j < matrix[i].size(); j++)
{
if (ssque.size() < k)
ssque.push(matrix[i][j]);
else
if (matrix[i][j] < ssque.top())
{
ssque.pop();
ssque.push(matrix[i][j]);
}
}
}
return ssque.top();
}
};