Programming to fight in the world 5-3

#-*- coding:utf-8 -*-

class Bitutils():
        
    def getNextArith(self,n):
        c = n
        c0 = 0
        c1 = 0
        while c & 1 == 0 and c != 0:
            c0 += 1
            c >>= 1
        
        while c & 1 == 1:
            c1 += 1
            c >>= 1
        if (c0 + c1 == 31 or c0 + c1 == 0):
            return -1
        return n + (1 << c0) + (1 << (c1 -1)) -1
    
    def getPrevArith(self,n):
        temp = n
        c0 = 0
        c1 = 0
        while temp & 1 == 1:
            c1 += 1
            temp >>= 1
            
        if temp == 0:
            return -1
        
        while temp & 1 == 0 and temp != 0:
            c0 += 1
            temp >>= 1
        
        
        return n - (1 << c1) - (1<<(c0 - 1)) + 1

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