LeetCode: 905. Sort Array By Parity
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 <= 5000
- 0 <= A[i] <= 5000
My solution
Using two pointer, one point next available space, one pointer switch from front to end, find even number;
var sortArrayByParity = function(A) {
let firstEven= 0;
for(let i = 0; i <= A.length; i++){
if(A[i]%2 == 0){
let temp = A[firstEven];
A[firstEven] = A[i];
A[i] = temp;
firstEven++;
}
}
return A;
};
Optimize:
Using QuickSort method
var sortArrayByParity = function(A) {
let i = 0, j = A.length - 1;
while(i < j){
if(A[i]%2 == 1 && A[j]%2 == 0){
let tmp = A[i];
A[i] = A[j];
A[j] = tmp;
}
if(A[i]%2 == 0) i++;
if(A[j]%2 == 1) j--;
}
return A;
};