HARD - Greedy - Implementation

Corner cases should be covered too. Did you cover them?

Author: rachitiitr

LeetCode/41.first-missing-positive.py

@@ -0,0 +1,14 @@
+class Solution:
+    def firstMissingPositive(self, nums: List[int]) -> int:
+        n = len(nums)
+        for i in range(n):
+            correctPos = nums[i]-1 # number 3 goes to index 2
+            while 1 <= nums[i] <= n and nums[i] != nums[correctPos]:
+                nums[i], nums[correctPos] = nums[correctPos], nums[i]
+                correctPos = nums[i]-1 # now nums[i] has changed
+                
+        
+        for i in range(n):
+            if i+1 != nums[i]:
+                return i+1
+        return n+1