max xor b/w a range

example.cpp

#include <bits/stdc++.h>
using namespace std;

int getMax(int L, int R) {
	int LxR = L ^ R;
	int p = 0;

	// msb of L ^ R
	while(LxR) {
		p++;
		LxR >>= 1;
	}

	int max = 0;
	int two = 1;
	while(p--) {
		max += two;
		two <<= 1;
	}
	return max;
}

int main() {

    #ifndef ONLINE_JUDGE
	    freopen("input.txt", "r", stdin);
	    freopen("output.txt", "w", stdout);
    #endif

int tc,L,R;
cin>>tc;

while(tc--) {
	cin>>L>>R;
	cout<<getMax(L,R)<<"\n";
}
return 0;
}