Adding Simple Solution for Problem - 1299 - Replace Elements on Right Side

Author: Vanditg

Replace_Elements_On_Right/SimpleSolution.py

@@ -0,0 +1,39 @@
+##==================================
+## Leetcode
+## Student: Vandit Jyotindra Gajjar
+## Year: 2020
+## Problem: 1299
+## Problem Name: Replace Elements with Greatest Element on Right Side
+##===================================
+#
+#Given an array arr, replace every element in that array with the greatest element among the elements to its right, and replace the last element with -1.
+#
+#After doing so, return the array.
+#
+#Example 1:
+#
+#Input: arr = [17,18,5,4,6,1]
+#Output: [18,6,6,6,1,-1]
+class Solution:
+    def replaceElements(self, array):
+        tmpArray = [-1 for _ in range(len(array))]   #Creating tmpArray and fill it up with -1 for len(array)
+        for i in range(len(array)) - 2, -1, -1):    #Loop through array in reverse manner.
+            tmpArray[i] = max(tmpArray[i + 1], array[i + 1])    #Update the tmpArray[i] by using max function between actual and tmpArray.
+        return tmpArray    #Returning tmpArray at the end.
+
+#Example
+#array = [17, 18, 5, 4, 6, 1]
+#tmpArray = [-1, -1, -1, -1, -1, -1]
+#Now range will be range(4, -1, -1)
+#array =    [17, 18,  5,  4,  6,  1]
+#tmpArray = [-1, -1, -1, -1, -1, -1]
+#Index =    [0,   1,  2,  3,  4,  5]
+#i = 4
+#tmpArray[4] = max(tmpArray[5], array[5]) = max(-1, 1) = 1
+#tmpArray = [-1, -1, -1, -1,  1,  -1]
+#array =    [17, 18,  5,  4,  6,  1]
+#i = 3
+#tmpArray[3] =max(tmpArray[4], array[4]) = max(1, 6) = 6
+#tmpArray = [-1, -1, -1,  6,  1,  -1]
+#array =    [17, 18,  5,  4,  6,  1]
+# and so on we'll get tmpArray = [18, 6, 6, 6, 1, -1]