Number whose sum of XOR with given array range is maximum | CPP program to find smallest integer X such that sum of its XOR with range is maximum . ; Function to make prefix array which counts 1 's of each bit up to that number ; Making a prefix array which sums number of 1 's up to that position ; If j - th bit of a number is set then add one to previously counted 1 's ; Function to find X ; Initially taking maximum value all bits 1 ; Iterating over each bit ; get 1 ' s ▁ at ▁ ith ▁ bit ▁ between ▁ the ▁ ▁ range ▁ L - R ▁ by ▁ subtracting ▁ 1' s till Rth number - 1 's till L-1th number ; If 1 ' s ▁ are ▁ more ▁ than ▁ or ▁ equal ▁ to ▁ 0' s then unset the ith bit from answer ; Set ith bit to 0 by doing Xor with 1 ; Driver program
#include <bits/stdc++.h> NEW_LINE using namespace std ; #define MAX  2147483647 NEW_LINE int one [ 100001 ] [ 32 ] ; void make_prefix ( int A [ ] , int n ) { for ( int j = 0 ; j < 32 ; j ++ ) one [ 0 ] [ j ] = 0 ; for ( int i = 1 ; i <= n ; i ++ ) { int a = A [ i - 1 ] ; for ( int j = 0 ; j < 32 ; j ++ ) { int x = pow ( 2 , j ) ; if ( a & x ) one [ i ] [ j ] = 1 + one [ i - 1 ] [ j ] ; else one [ i ] [ j ] = one [ i - 1 ] [ j ] ; } } } int Solve ( int L , int R ) { int l = L , r = R ; int tot_bits = r - l + 1 ; int X = MAX ; for ( int i = 0 ; i < 31 ; i ++ ) { int x = one [ r ] [ i ] - one [ l - 1 ] [ i ] ; if ( x >= tot_bits - x ) { int ith_bit = pow ( 2 , i ) ; X = X ^ ith_bit ; } } return X ; } int main ( ) { int n = 5 , q = 3 ; int A [ ] = { 210 , 11 , 48 , 22 , 133 } ; int L [ ] = { 1 , 4 , 2 } , R [ ] = { 3 , 14 , 4 } ; make_prefix ( A , n ) ; for ( int j = 0 ; j < q ; j ++ ) cout << Solve ( L [ j ] , R [ j ] ) << endl ; return 0 ; }