输入一个长度为 n 整数数组,实现一个函数来调整该数组中数字的顺序,使得所有的奇数位于数组的前面部分, 所有的偶数位于数组的后面部分,并保证奇数和奇数,偶数和偶数之间的相对位置不变.

方法1：

1. 第一遍遍历,将奇数、Even numbers are put into two arrays respectively.（cntOdd number recorded,cnt2Even numbers are recorded）
2. Put the even numbers into the odd number array as a result.

public int[] reOrderArray1(int[] array) {
    
        int len = array.length;
        int[] array1 = new int[len];
        int[] array2 = new int[len];

        int cnt = 0;
        int cnt2 = 0;
        for (int j : array) {
    
            if ((j & 1) != 0) {
    
                array1[cnt++] = j;
            } else {
    
                array2[cnt2++] = j;
            }
        }
        System.arraycopy(array2,0,array1,cnt,cnt2);
        return array1 ;
    }

方法2：

1. The first pass traverses the number of odd records
2. Then take a double pointer,One loop will be odd、Even numbers are put into the result array.

    public int[] reOrderArray(int[] array) {
    
        int[] res=new int[array.length];
        int cnt = 0;
        for (int j : array) {
    
            if ((j & 1) != 0) {
    
                cnt++;
            }
        }
        int x=0,y=cnt;
        for(int j : array){
    
            if((j&1)!=0){
    
                res[x++] = j;
            } else {
    
                res[y++]=j;
            }
        }
        return res;
    }

努力、奋斗！