劍指offer 最小的k個數

題目

輸入n個整數，找出其中最小的K個數。例如輸入4,5,1,6,2,7,3,8這8個數字，則最小的4個數字是1,2,3,4,。

思路

partition

代碼

# -*- coding:utf-8 -*-
class Solution:
    def partition(self, tinput, left, right):
        leftIndex = left
        tmp = tinput[left]
        while left <= right:
            while left <= right and tinput[left] <= tmp: left += 1
            while left <= right and tinput[right] > tmp: right -= 1
            if left <= right: tinput[left], tinput[right] = tinput[right], tinput[left]
        tinput[leftIndex], tinput[right] = tinput[right], tinput[leftIndex]
        return right
    def GetLeastNumbers_Solution(self, tinput, k):
        # write code here
        if k == 0 or not tinput or k > len(tinput): return []
        part = self.partition(tinput, 0, len(tinput) - 1)
        left = 0; right = len(tinput) - 1
        while part != k - 1:
            if part < k - 1:
                left = part + 1
            else:
                right = part - 1
            part = self.partition(tinput, left, right)
        return sorted(tinput[:k])