Adjust the array order so that odd numbers precede even numbers and their relative positions remain the same

1. Power button _ Adjust the array so that odd numbers precede even numbers

Possible changes in relative position ： With two pointers left、right, Traverse left and right at the same time , Left even stop traversal , The odd number on the right stops traversing , In exchange for left and right The corresponding value is just .

/**
 *  Enter an array of integers , Implement a function to adjust the order of the Numbers in the array , Make all odd numbers in the first half of the array , All even numbers are in the second half of the array .
 **/
public class Num21_ Odd numbers precede even numbers  {
    public  int[] exchange(int[] nums) {
        // Double pointer i,j,i Point to the front ,j Point to the back ,i Find an even number ,j Find odd number , Find the exchange 
        int i=0;
        int j=nums.length-1;
        while(i<j){
            while((i<j)&&(nums[i]&1)!=0){// Odd number 
                i++;
            }
            while((i<j)&&(nums[j]&1)==0){
                j--;
            }
            if(i<j){
                swap(nums,i,j);
            }


        }
        return nums;
    }

    private  void swap(int[] nums, int i, int j) {
        int t=nums[i];
        nums[i]=nums[j];
        nums[j]=t;
    }

}

2. Adjust the array order so that odd numbers precede even numbers and their relative positions remain unchanged __ Cattle from

Ideas ： Using the idea of insertion sorting , Odd numbers can be inserted forward continuously

import java.util.*;
public class Solution {
    public void reOrderArray(int [] array) {
        int len=array.length;
        int k=0;// Record the number of odd numbers that have been sorted 
        for(int i=0;i<len;i++){
            if((array[i]&1)==1){
                int j=i;
                // Put an odd number j Exchange to k+1 Location 【 Odd numbers are constantly inserted forward 】
                while(j>k){
                    int temp=array[j];
                    array[j]=array[j-1];
                    array[j-1]=temp;
                    j--;
                }
                // Out of cycle odd j Just swap it k+1 Location ,k++ Continue to cycle 
                k++;
            }
        }
        
    }
}