"Leetcode-Interview algorithm classic-java implementation" "215-kth largest Element in an array (number of K in array)"

"215-kth largest Element in an array (number of k large in array)" "leetcode-Interview algorithm classic-java Implementation" "All topics Directory Index" code Download "Https://github.com/Wang-Jun-Chao" Original Question

Find the kth largest element in an unsorted array. Note that it was the kth largest element in the sorted order and not the kth distinct element.
For example,
Given [3,2,1,5,6,4] and k = 2, return 5.
Note:
You may assume k are always valid, 1≤k≤array ' s length.

Main Topic

Find the element of the K-Large from an unordered array. Note that the K-large after sorting, and not the K-non-repeating element can assume that K must be valid, 1≤k≤ array length

Thinking of solving problems

O (n) Solution: Fast selection (Quickselect) algorithm

Code Implementation

Algorithm implementation class

Import java.util.Collections; Public classSolution { Public int findkthlargest(int[] Nums,intK) {if(K <1|| Nums = =NULL|| Nums.length < K) {Throw NewIllegalArgumentException (); }returnFindkthlargest (Nums,0, Nums.length-1, k); } Public int findkthlargest(int[] Nums,intStartintEndintK) {//Center value        intPivot = Nums[start];intLo = start;inthi = end; while(Lo < HI) {//Move the number less than the center value to the left of the array             while(Lo < hi && Nums[hi] >= pivot)            {hi--; } Nums[lo] = Nums[hi];//Move the number greater than the center value to the right of the array             while(Lo < hi && Nums[lo] <= pivot)            {lo++;        } Nums[hi] = Nums[lo]; } Nums[lo] = pivot;//If you have found        if(End-lo +1= = k) {returnPivot }//K-large number at the right of Lo position        Else if(End-lo +1> k) {returnFindkthlargest (Nums, lo +1, end, K); }//K-large number at the left of the LO position        Else{//K (end-lo+1)            //(END-LO+1): Indicates the number of elements from the LO position to the end position, or the right half.            //The original K-Large becomes K (end-lo+1) Large            returnFindkthlargest (nums, Start, lo-1, K-(End-lo +1)); }    }}

Evaluation Results

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"Leetcode-Interview algorithm classic-java implementation" "215-kth largest Element in an array (number of K in array)"