Merge pull request neetcode-gh#1866 from itsrishub/main

Create 0041-first-missing-positive.java

java/0041-first-missing-positive.java

@@ -0,0 +1,31 @@
+class Solution {
+ public int firstMissingPositive(int[] nums) {
+ int n = nums.length, size = 0;
+
+ while(n > 0){
+ n = n>>1;
+ size++;
+ }
+ n = nums.length;
+ int pivot = 0;
+
+
+ for(int i = 0; i < n; i++){
+ if(nums[i] <= 0 || nums[i] > n){
+ int temp = nums[i];
+ nums[i] = nums[pivot];
+ nums[pivot] = temp;
+ pivot++;
+ }
+ }
+ for(int i= 0; i < pivot; i++)
+ nums[i] = 0;
+ for(int i= pivot; i < n; i++){
+ nums[(nums[i] - 1)&((1<<size) - 1)] |= (1<<size);
+ }
+ for(int i= 0; i < n; i++)
+ if((nums[i] & (1<<size)) == 0)
+ return i+1;
+ return n+1;
+ }
+}