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UVa 12444 Bits Pieces

UVa 12444 Bits Pieces

Method: Bitmasking, Bit manipulation
Trick: Analyze the problem a bit with the given Samples.
When for a particular bit
C = 1 & D = 1, obviously both the numbers have to have 1 in that position
C = 0 & D = 1, if this case occurs for the first time make the bit in B = 1 & A = 0, otherwise B = 0 & A = 1. This ensures |B-A] Minimality & A<=B.
No other combination is possible.

/* Faith-M */

//Headers
#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <climits>
#include <clocale>
//Defines
#define pow2(i) (1<<i)
#define bit(i) (1<<i)
#define isOdd(i) (i&1)
#define isEven(i) (!(i&1))
#define isPrime(i) ((i==2) || ((i&1) && !pTest[i])) //pTest has to be the bool arrays name
#define sz(i) i.size()
#define vec(type,name) vector< type > name
#define rep(i,a,b) for(int i=a ; i<=b ; i++)
#define swap(type,a,b) {type t=a; a=b; b=t;}
#define sum(a,n) ( (n*(n+1)/2) - (a-1)*a/2 )
#define iscap(i) (i>=A&&i<=Z)
#define issmall(i) (i>=a&&i<=z)
#define isnum(i) (i>=0&&i<=9)
#define issymbol(i) (!(i>=a&&i<=z) && !(i>=A&&i<=Z) && !(i>=0&&i<=9))
#define mk(i,j) make_pair(i,j)
#define ERROR 1e-11
//Type Defs
typedef long long lint;
typedef unsigned long long ulint;
typedef long double ldouble;

using namespace std;

pair <lint, lint> find( lint c, lint d )
{
 lint a=0, b=0, bit_c, bit_d;
 bool fbit=true;
 int i;

 for (i=31 ; i>=0 ; i--)
 {
 if ((1<<i)&c) bit_c = 1;
 else bit_c = 0;

 if ((1<<i)&d) bit_d = 1;
 else bit_d = 0;

 if (bit_c == 1 && bit_d == 1)
 {
 a = a | (1<<i);
 b = b | (1<<i);
 } else if (bit_c == 0 && bit_d == 1)
 {
 if (fbit == true)
 {
 b = b | (1<<i);
 } else
 {
 a = a | (1<<i);
 }
 fbit = false;
 }
 }

 if ( (a&b) == c && (a|b) == d ) return make_pair(a,b);
 else return make_pair(-1,-1);

}

int main()
{
 //freopen("input.txt","r+",stdin);
 //freopen("output.txt","w+",stdout);/**/

 // TEST CASE //
 int kase=1, kounter=1;/**/

 lint c, d;

 scanf("%d",&kase);
 while (kase--)
 {
 cin >> c >> d;

 pair <lint, lint> res = find(c,d);

 if (res.first == -1) printf("-1 ");
 else cout << res.first << " " << res.second << endl;
 }


 return 0;
}

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