The challenge
Given an array A of non-negative integers, return an array consisting of all the even elements of A, followed by all the odd elements of A.
You may return any answer array that satisfies this condition.
Example 1:
Input: [3,1,2,4] Output: [2,4,3,1] The outputs [4,2,3,1], [2,4,1,3], and [4,2,1,3] would also be accepted.
Note:
1 <= A.length <= 50000 <= A[i] <= 5000
The solution
class Solution {
// return a sorted primitive int array
public int[] sortArrayByParity(int[] A) {
// keep track of place
int lastIndex = 0;
// loop through input array
for (int i=0; i<A.length; i++) {
// if we found an even number
if (A[i]%2==0) {
// keep track of the values
int lastValue = A[lastIndex];
int thisValue = A[i];
// swap the values
A[i] = lastValue;
A[lastIndex] = thisValue;
// increment our swap index
lastIndex++;
}
}
// return a sorted array
return A;
}
}
