LeetCode_27---Remove Element

Given an array and a value, remove all instances of that value in place and return the new length.
The order of elements can be changed. It doesn't matter what you leave beyond the new length.

翻译：

Code:

package mengdexinTest;

import java.util.Arrays;

public class LeetCode27 {
//340ms --- 两头走
public static int removeElement(int[] nums, int val) {
int i = 0, j = nums.length - 1;
System.out.println("1j：" + j);
while (i <= j) {
while (i < nums.length && nums[i] != val) {
i++;
}
while (j >= 0 && nums[j] == val) {
j--;
}
System.out.println("2j：" + j);
if (i < j) {
nums[i] = nums[j];
--j;
++i;
}
System.out.println("3j：" + j);
}
System.out.println("4j：" + j);
return j+1;
}

// 316msA --- 一头走
public static int removeElement1(int[] nums, int val) {
int i = 0, j = 0, n = nums.length;
while (j < n) {
if (nums[j] != val) {
nums[i] = nums[j];
++i;
}
++j;
}
return i;
}
//332msA --- 一前一後
public static int removeElement2(int[] nums, int val) {
int i = 0, j = 0, n = nums.length;
while (j < n) {
if(nums[j]!= val){
nums[i++] = nums[j];
}
++j;
}
return i;
}

public static void main(String[] args) {
int[] a = { 1, 2, 2, 2, 3, 3, 6, 9 };
int[] b = { 1, 2, 3 };
int[] c = { 2, 2, 2 };
int[] d = { 4,5 };
int e = 2;
System.out.println("第二种：" + removeElement(a, e));
System.out.println("第二种：" + Arrays.toString(a));
}

}