Created P08_XorAndProject.py

CompetitiveProgramming/HackerEarth/Bit_Manipulation/P08_XorAndProject.py

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+# A project was going on related to image processing and to perform experiments and get desired result the image needs to be converted to 
+# Gray-Scale using a parameter 'x' and the function P(x) represented the Gray-Code and calculated via x xor (x div 2) where xor stands for 
+# bitwise exclusive OR (bitwise modulo 2 addition), and div means integer division.
+
+# It is interesting to note that function P(x) is invertible, which means it is always possible to uniquely restore x given the value of 
+# P(x).
+
+# So the group working on the project forgot to keep the original data related to parameter 'x'. Write a program to restore number x from 
+# the given value of P(x).
+
+# INPUT:
+# The input file contains an integer number y, the value of G(x).
+
+# OUTPUT:
+# The output file should contain a single integer x such that G(x) = y.
+
+# CONSTRAINTS:
+# 0 ≤ x,P(x) ≤ .
+
+# SAMPLE INPUT 
+# 15
+# SAMPLE OUTPUT 
+# 10
+
+a=int(input())
+a=bin(a).replace("0b","")
+c=[int(i) for i in str(a)] 
+d=[]
+e=c[0]
+for i in range(0,len(a)):
+    if(i==0):
+        d.append(c[i])
+    else:
+        f=c[i]^e
+        d.append(f)
+        e=f
+e=1
+g=0
+for i in range(0,len(a)):
+    g=g+d[len(a)-i-1]*e
+    e=e*2
+print(g)