PreCompute and store the powers of 2
vector < int > powersOfTwo ( 11 ) ; powersOfTwo [ 0 ] = 1 ; for ( int i = 1 ; i < 11 ; i ++ ) { powersOfTwo [ i ] = powersOfTwo [ i - 1 ] * 2 ; } int ctr = 1 ; int ans = 0 ; while ( N > 0 ) {