Count no . of ordered subsets having a particular XOR value | Returns count of ordered subsets of arr [ ] with XOR value = K ; Find maximum element in arr [ ] ; Maximum possible XOR value ; The value of dp [ i ] [ j ] [ k ] is the number of subsets of length k having XOR of their elements as j from the set arr [ 0. . . i - 1 ] ; Initializing all the values of dp [ i ] [ j ] [ k ] as 0 ; The xor of empty subset is 0 ; Fill the dp table ; The answer is the number of subsets of all lengths from set arr [ 0. . n - 1 ] having XOR of elements as k ; Driver Code
function subsetXOR ( arr , n , K ) { let max_ele = arr [ 0 ] ; for ( let i = 1 ; i < n ; i ++ ) if ( arr [ i ] > max_ele ) max_ele = arr [ i ] ; let m = ( 1 << parseInt ( Math . log ( max_ele ) / Math . log ( 2 ) + 1 , 10 ) ) - 1 ; let dp = new Array ( n + 1 ) ; for ( let i = 0 ; i <= n ; i ++ ) { dp [ i ] = new Array ( m + 1 ) ; for ( let j = 0 ; j <= m ; j ++ ) { dp [ i ] [ j ] = new Array ( n + 1 ) ; for ( let k = 0 ; k <= n ; k ++ ) { dp [ i ] [ j ] [ k ] = 0 ; } } } for ( let i = 0 ; i <= n ; i ++ ) dp [ i ] [ 0 ] [ 0 ] = 1 ; for ( let i = 1 ; i <= n ; i ++ ) { for ( let j = 0 ; j <= m ; j ++ ) { for ( let k = 0 ; k <= n ; k ++ ) { dp [ i ] [ j ] [ k ] = dp [ i - 1 ] [ j ] [ k ] ; if ( k != 0 ) { dp [ i ] [ j ] [ k ] += k * dp [ i - 1 ] [ j ^ arr [ i - 1 ] ] [ k - 1 ] ; } } } } let ans = 0 ; for ( let i = 1 ; i <= n ; i ++ ) { ans += dp [ n ] [ K ] [ i ] ; } return ans ; } let arr = [ 1 , 2 , 3 ] ; let k = 1 ; let n = arr . length ; document . write ( subsetXOR ( arr , n , k ) ) ;