最小异或值对

给定一个整数数组。在具有最小XOR值的数组中查找该对。 例如:

null
Input : arr[] =  {9, 5, 3}Output : 6        All pair with xor value (9 ^ 5) => 12,         (5 ^ 3) => 6, (9 ^ 3) => 10.        Minimum XOR value is 6Input : arr[] = {1, 2, 3, 4, 5}Output : 1 

A. 简单解决方案 就是生成给定数组的所有对,并计算其值的异或。最后,返回最小XOR值。这个解需要O(n) 2. )时间到了。

C++

// C++ program to find minimum XOR value in an array.
#include <bits/stdc++.h>
using namespace std;
// Returns minimum xor value of pair in arr[0..n-1]
int minXOR( int arr[], int n)
{
int min_xor = INT_MAX; // Initialize result
// Generate all pair of given array
for ( int i = 0; i < n; i++)
for ( int j = i + 1; j < n; j++)
// update minimum xor value if required
min_xor = min(min_xor, arr[i] ^ arr[j]);
return min_xor;
}
// Driver program
int main()
{
int arr[] = { 9, 5, 3 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << minXOR(arr, n) << endl;
return 0;
}


JAVA

// Java program to find minimum XOR value in an array.
class GFG {
// Returns minimum xor value of pair in arr[0..n-1]
static int minXOR( int arr[], int n)
{
int min_xor = Integer.MAX_VALUE; // Initialize result
// Generate all pair of given array
for ( int i = 0 ; i < n; i++)
for ( int j = i + 1 ; j < n; j++)
// update minimum xor value if required
min_xor = Math.min(min_xor, arr[i] ^ arr[j]);
return min_xor;
}
// Driver program
public static void main(String args[])
{
int arr[] = { 9 , 5 , 3 };
int n = arr.length;
System.out.println(minXOR(arr, n));
}
}
// This code is contributed by Sumit Ghosh


Python3

# Python program to find minimum
# XOR value in an array.
# Function to find minimum XOR pair
def minXOR(arr, n):
# Sort given array
arr.sort();
min_xor = 999999
val = 0
# calculate min xor of
# consecutive pairs
for i in range ( 0 , n - 1 ):
for j in range (i + 1 , n - 1 ):
# update minimum xor value
# if required
val = arr[i] ^ arr[j]
min_xor = min (min_xor, val)
return min_xor
# Driver program
arr = [ 9 , 5 , 3 ]
n = len (arr)
print (minXOR(arr, n))
# This code is contributed by Sam007.


C#

// C# program to find minimum
// XOR value in an array.
using System;
class GFG {
// Returns minimum xor value of
// pair in arr[0..n-1]
static int minXOR( int [] arr, int n)
{
// Initialize result
int min_xor = int .MaxValue;
// Generate all pair of given array
for ( int i = 0; i < n; i++)
for ( int j = i + 1; j < n; j++)
// update minimum xor value if required
min_xor = Math.Min(min_xor, arr[i] ^ arr[j]);
return min_xor;
}
// Driver program
public static void Main()
{
int [] arr = { 9, 5, 3 };
int n = arr.Length;
Console.WriteLine(minXOR(arr, n));
}
}
// This code is contributed by Sam007


PHP

<?php
// PHP program to find minimum
// XOR value in an array.
// Returns minimum xor value
// of pair in arr[0..n-1]
function minXOR( $arr , $n )
{
// Initialize result
$min_xor = PHP_INT_MAX;
// Generate all pair of given array
for ( $i = 0; $i < $n ; $i ++)
for ( $j = $i + 1; $j < $n ; $j ++)
// update minimum xor
// value if required
$min_xor = min( $min_xor , $arr [ $i ] ^ $arr [ $j ]);
return $min_xor ;
}
// Driver Code
$arr = array (9, 5, 3);
$n = count ( $arr );
echo minXOR( $arr , $n );
// This code is contributed by anuj_67.
?>


Javascript

<script>
// Javascript program to find
// minimum XOR value in an array.
// Returns minimum xor value of pair in arr[0..n-1]
function minXOR(arr, n)
{
// Initialize result
let min_xor = Number.MAX_VALUE;
// Generate all pair of given array
for (let i = 0; i < n; i++)
for (let j = i + 1; j < n; j++)
// update minimum xor value if required
min_xor = Math.min(min_xor, arr[i] ^ arr[j]);
return min_xor;
}
// Driver program
let arr = [ 9, 5, 3 ];
let n = arr.length;
document.write(minXOR(arr, n));
</script>


输出:

6

有效解决方案 可以在O(nlogn)时间内解决此问题。以下是算法:

1). Sort the given array2). Traverse and check XOR for every consecutive pair

以下是上述方法的实施情况:

C++

#include <bits/stdc++.h>
using namespace std;
// Function to find minimum XOR pair
int minXOR( int arr[], int n)
{
// Sort given array
sort(arr, arr + n);
int minXor = INT_MAX;
int val = 0;
// calculate min xor of consecutive pairs
for ( int i = 0; i < n - 1; i++) {
val = arr[i] ^ arr[i + 1];
minXor = min(minXor, val);
}
return minXor;
}
// Driver program
int main()
{
int arr[] = { 9, 5, 3 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << minXOR(arr, n) << endl;
return 0;
}


JAVA

import java.util.Arrays;
class GFG {
// Function to find minimum XOR pair
static int minXOR( int arr[], int n)
{
// Sort given array
Arrays.parallelSort(arr);
int minXor = Integer.MAX_VALUE;
int val = 0 ;
// calculate min xor of consecutive pairs
for ( int i = 0 ; i < n - 1 ; i++) {
val = arr[i] ^ arr[i + 1 ];
minXor = Math.min(minXor, val);
}
return minXor;
}
// Driver program
public static void main(String args[])
{
int arr[] = { 9 , 5 , 3 };
int n = arr.length;
System.out.println(minXOR(arr, n));
}
}
// This code is contributed by Sumit Ghosh


Python3

import sys
# Function to find minimum XOR pair
def minXOR(arr, n):
# Sort given array
arr.sort()
minXor = int (sys.float_info. max )
val = 0
# calculate min xor of consecutive pairs
for i in range ( 0 ,n - 1 ):
val = arr[i] ^ arr[i + 1 ];
minXor = min (minXor, val);
return minXor
# Driver program
arr = [ 9 , 5 , 3 ]
n = len (arr)
print (minXOR(arr, n))
# This code is contributed by Sam007.


C#

// C# program to find minimum
// XOR value in an array.
using System;
class GFG {
// Function to find minimum XOR pair
static int minXOR( int [] arr, int n)
{
// Sort given array
Array.Sort(arr);
int minXor = int .MaxValue;
int val = 0;
// calculate min xor of consecutive pairs
for ( int i = 0; i < n - 1; i++) {
val = arr[i] ^ arr[i + 1];
minXor = Math.Min(minXor, val);
}
return minXor;
}
// Driver program
public static void Main()
{
int [] arr = { 9, 5, 3 };
int n = arr.Length;
Console.WriteLine(minXOR(arr, n));
}
}
// This code is contributed by Sam007


PHP

<?php
// Function to find minimum XOR pair
function minXOR( $arr , $n )
{
// Sort given array
sort( $arr );
$minXor = PHP_INT_MAX;
$val = 0;
// calculate min xor
// of consecutive pairs
for ( $i = 0; $i < $n - 1; $i ++)
{
$val = $arr [ $i ] ^ $arr [ $i + 1];
$minXor = min( $minXor , $val );
}
return $minXor ;
}
// Driver Code
$arr = array (9, 5, 3);
$n = count ( $arr );
echo minXOR( $arr , $n );
// This code is contributed by Smitha.
?>


Javascript

<script>
// Function to find minimum XOR pair
function minXOR(arr, n)
{
// Sort given array
arr.sort();
let minXor = Number.MAX_VALUE;
let val = 0;
// calculate min xor of consecutive pairs
for (let i = 0; i < n - 1; i++) {
val = arr[i] ^ arr[i + 1];
minXor = Math.min(minXor, val);
}
return minXor;
}
// Driver program
let arr = [ 9, 5, 3 ];
let n = arr.length;
document.write(minXOR(arr, n));
</script>


输出:

6

时间复杂度:O(N*logN) 空间复杂性:O(1) 感谢乌特卡什·古普塔提出上述方法。 更进一步 有效解决方案 在假设整数存储位数固定的情况下,可以在O(n)时间内解决上述问题。其想法是使用Trie数据结构。下面是算法。

1). Create an empty trie. Every node of trie contains two children    for 0 and 1 bits.2). Initialize min_xor = INT_MAX, insert arr[0] into trie3). Traversal all array element one-by-one starting from second.     a. First find minimum setbet difference value in trie         do xor of current element with minimum setbit diff that value      b. update min_xor value if required     c. insert current array element in trie 4). return min_xor  

下面是上述算法的实现。

C++

// C++ program to find minimum XOR value in an array.
#include <bits/stdc++.h>
using namespace std;
#define INT_SIZE 32
// A Trie Node
struct TrieNode {
int value; // used in leaf node
TrieNode* Child[2];
};
// Utility function to create a new Trie node
TrieNode* getNode()
{
TrieNode* newNode = new TrieNode;
newNode->value = 0;
newNode->Child[0] = newNode->Child[1] = NULL;
return newNode;
}
// utility function insert new key in trie
void insert(TrieNode* root, int key)
{
TrieNode* temp = root;
// start from the most significant bit, insert all
// bit of key one-by-one into trie
for ( int i = INT_SIZE - 1; i >= 0; i--) {
// Find current bit in given prefix
bool current_bit = (key & (1 << i));
// Add a new Node into trie
if (temp->Child[current_bit] == NULL)
temp->Child[current_bit] = getNode();
temp = temp->Child[current_bit];
}
// store value at leafNode
temp->value = key;
}
// Returns minimum XOR value of an integer inserted
// in Trie and given key.
int minXORUtil(TrieNode* root, int key)
{
TrieNode* temp = root;
for ( int i = INT_SIZE - 1; i >= 0; i--) {
// Find current bit in given prefix
bool current_bit = (key & (1 << i));
// Traversal Trie, look for prefix that has
// same bit
if (temp->Child[current_bit] != NULL)
temp = temp->Child[current_bit];
// if there is no same bit.then looking for
// opposite bit
else if (temp->Child[1 - current_bit] != NULL)
temp = temp->Child[1 - current_bit];
}
// return xor value of minimum bit difference value
// so we get minimum xor value
return key ^ temp->value;
}
// Returns minimum xor value of pair in arr[0..n-1]
int minXOR( int arr[], int n)
{
int min_xor = INT_MAX; // Initialize result
// create a True and insert first element in it
TrieNode* root = getNode();
insert(root, arr[0]);
// Traverse all array element and find minimum xor
// for every element
for ( int i = 1; i < n; i++) {
// Find minimum XOR value of current element with
// previous elements inserted in Trie
min_xor = min(min_xor, minXORUtil(root, arr[i]));
// insert current array value into Trie
insert(root, arr[i]);
}
return min_xor;
}
// Driver code
int main()
{
int arr[] = { 9, 5, 3 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << minXOR(arr, n) << endl;
return 0;
}


JAVA

// Java program to find minimum XOR value in an array.
class GFG {
static final int INT_SIZE = 32 ;
// A Trie Node
static class TrieNode {
int value; // used in leaf node
TrieNode[] Child = new TrieNode[ 2 ];
public TrieNode()
{
value = 0 ;
Child[ 0 ] = null ;
Child[ 1 ] = null ;
}
}
static TrieNode root;
// utility function insert new key in trie
static void insert( int key)
{
TrieNode temp = root;
// start from the most significant bit, insert all
// bit of key one-by-one into trie
for ( int i = INT_SIZE - 1 ; i >= 0 ; i--) {
// Find current bit in given prefix
int current_bit = (key & ( 1 << i)) >= 1 ? 1 : 0 ;
// Add a new Node into trie
if (temp != null && temp.Child[current_bit] == null )
temp.Child[current_bit] = new TrieNode();
temp = temp.Child[current_bit];
}
// store value at leafNode
temp.value = key;
}
// Returns minimum XOR value of an integer inserted
// in Trie and given key.
static int minXORUtil( int key)
{
TrieNode temp = root;
for ( int i = INT_SIZE - 1 ; i >= 0 ; i--) {
// Find current bit in given prefix
int current_bit = (key & ( 1 << i)) >= 1 ? 1 : 0 ;
// Traversal Trie, look for prefix that has
// same bit
if (temp.Child[current_bit] != null )
temp = temp.Child[current_bit];
// if there is no same bit.then looking for
// opposite bit
else if (temp.Child[ 1 - current_bit] != null )
temp = temp.Child[ 1 - current_bit];
}
// return xor value of minimum bit difference value
// so we get minimum xor value
return key ^ temp.value;
}
// Returns minimum xor value of pair in arr[0..n-1]
static int minXOR( int arr[], int n)
{
int min_xor = Integer.MAX_VALUE; // Initialize result
// create a True and insert first element in it
root = new TrieNode();
insert(arr[ 0 ]);
// Traverse all array element and find minimum xor
// for every element
for ( int i = 1 ; i < n; i++) {
// Find minimum XOR value of current element with
// previous elements inserted in Trie
min_xor = Math.min(min_xor, minXORUtil(arr[i]));
// insert current array value into Trie
insert(arr[i]);
}
return min_xor;
}
// Driver code
public static void main(String args[])
{
int arr[] = { 9 , 5 , 3 };
int n = arr.length;
System.out.println(minXOR(arr, n));
}
}
// This code is contributed by Sumit Ghosh


python

# class for the basic Trie Node
class TrieNode:
def __init__( self ):
# Child array with 0 and 1
self .child = [ None ] * 2
# meant foor the lead Node
self .value = None
class Trie:
def __init__( self ):
# initialise the root Node
self .root = self .getNode()
def getNode( self ):
# get a new Trie Node
return TrieNode()
# inserts a new element
def insert( self ,key):
temp = self .root
# 32 bit valued binary digit
for i in range ( 31 , - 1 , - 1 ):
# finding the bit at ith position
curr = (key>>i)&( 1 )
# if the child is None create one
if (temp.child[curr] is None ):
temp.child[curr] = self .getNode()
temp = temp.child[curr]
# add value to the leaf node
temp.value = key
# traverse the trie and xor with the most similar element
def xorUtil( self ,key):
temp = self .root
# 32 bit valued binary digit
for i in range ( 31 , - 1 , - 1 ):
# finding the bit at ith position
curr = (key>>i)& 1
# traverse for the same bit
if (temp.child[curr] is not None ):
temp = temp.child[curr]
# traverse if the same bit is not set in trie
elif (temp.child[ 1 - curr] is not None ):
temp = temp.child[ 1 - curr]
# return with the xor of the value
return temp.value^key
def minXor(arr):
# set m to a large number
m = 2 * * 30
# initialize Trie
trie = Trie()
# insert the first element
trie.insert(arr[ 0 ])
# for each element in the array
for i in range ( 1 , len (arr)):
# find the minimum xor value
m = min (m,trie.xorUtil(arr[i]))
# insert the new element
trie.insert(arr[i])
return m
# Driver Code
if __name__ = = "__main__" :
sample = [ 9 , 5 , 3 ]
print (minXor(sample))
#code contributed by Ashwin Bhat


输出:

6

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