Create Sort Array 0-1-2.md

Author: CodingWallah

Sort Array 0-1-2.md

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+### [Back2Home](https://github.com/CodingWallah/Arrays-DSA-Coding-Questions) | [Go2Video](#)
+```java
+
+//Best Solution 1 || Time = O(n) , Space = O(1)
+class Solution {
+ public void sortColors(int[] nums) {
+ int start = 0;
+ int end = nums.length - 1;
+ int ptr = 0, temp = 0;
+ while (ptr <= end) {
+ switch (nums[ptr]) {
+ case 0: {
+ temp = nums[start];
+ nums[start] = nums[ptr];
+ nums[ptr] = temp;
+ start++;
+ ptr++;
+ break;
+ }
+ case 1:
+ ptr++;
+ break;
+ case 2: {
+ temp = nums[ptr];
+ nums[ptr] = nums[end];
+ nums[end] = temp;
+ end--;
+ break; 
+ }
+ }
+ }
+ }
+}
+
+```
+
+```java
+
+//Solution2 - time complexity = O(n) | space = O(1)
+class Solution {
+ public void sortColors(int[] nums) {
+ int i=0, cnt0 = 0, cnt1 = 0, cnt2 = 0;
+ for (i = 0; i < nums.length; i++) {
+ if(nums[i]==0) 
+ cnt0++;
+ else if(nums[i]==1) 
+ cnt1++;
+ else if(nums[i]==2) 
+ cnt2++;
+ }
+ 
+ i = 0;
+ 
+ while (cnt0 > 0) {
+ nums[i++] = 0;
+ cnt0--;
+ }
+ 
+ while (cnt1 > 0) {
+ nums[i++] = 1;
+ cnt1--;
+ }
+ 
+ while (cnt2 > 0) {
+ nums[i++] = 2;
+ cnt2--;
+ }
+ }
+}
+
+```
+
+```java
+
+//sol3 || Time = O(nlogn)
+ class Solution {
+ public void sortColors(int[] nums) {
+ Arrays.sort(nums);
+ }
+}
+```