1 #define _for(i,a,b) for(int i = (a);i < (b);i ++) 2 class Solution 3 { 4     public: 5         int bitwiseComplement(int N) 6         { 7             if(N==0) 8                 return 1; 9             string s;10             while(N)11             {12                 s+= N%2+'0';13                 N/=2;14             }15             reverse(s.begin(),s.end());16         17             _for(i,0,s.size())18             {19                 if(s[i]=='0')20                 {21                     s[i] = '1';22                 }23                 else24                     s[i] = '0';25             }26             27             int rnt = 0;28             for(int i = 0 ;i < s.size();i ++)29             {30                 rnt += (s[i]-'0')*pow(2,s.size()-i-1);31               //  cout << rnt << endl;32             }33             return rnt;34         }35 };