Minimum value of N such that xor from 1 to N is equal to K | Function to find the value of N ; variable to store the result ; handling case for '0' ; handling case for '1' ; when number is completely divided by 4 then minimum ' x ' will be ' k ' ; when number divided by 4 gives 3 as remainder then minimum ' x ' will be ' k - 1' ; else it is not possible to get k for any value of x ; let the given number be 7
function findN ( k ) { var ans ; if ( k == 0 ) ans = 3 ; if ( k == 1 ) ans = 1 ; else if ( k % 4 == 0 ) ans = k ; else if ( k % 4 == 3 ) ans = k - 1 ; else ans = - 1 ; return ans ; } var k = 7 ; var res = findN ( k ) ; if ( res == - 1 ) document . write ( " " ) ; else document . write ( res ) ;