Merge pull request #134 from dsrao711/issue_131

Python solution for next permutation

Author: smv1999

DSA 450 GFG/next_permutation.py

@@ -0,0 +1,34 @@
+# Link for the problem : https://leetcode.com/problems/next-permutation/
+
+
+class Solution(object):
+    
+    def nextPermutation(self, nums):
+      found = False
+      i = len(nums)-2
+      while i >=0:
+         if nums[i] < nums[i+1]:
+            found =True
+            break
+         i-=1
+      if not found:
+         nums.sort()
+      else:
+         m = self.findMaxIndex(i+1,nums,nums[i])
+         nums[i],nums[m] = nums[m],nums[i]
+         nums[i+1:] = nums[i+1:][::-1]
+      return nums
+  
+    def findMaxIndex(self,index,a,curr):
+      ans = -1
+      index = 0
+      for i in range(index,len(a)):
+         if a[i]>curr:
+            if ans == -1:
+               ans = curr
+               index = i
+            else:
+               ans = min(ans,a[i])
+               index = i
+      return index
+ob1 = Solution()