从除相同索引的元素之外的所有元素的异或数组中构建以 K 开头的原始数组

原文:https://www . geeksforgeeks . org/construct-original-array-从所有元素的异或数组开始-除了相同索引处的元素/

给定一个由 N 个整数和数组的第一个元素B【】组成的数组A【】作为 K ,任务是从A【】构造数组B【】,使得对于任何索引 iA【I】所有数组元素的位异或

示例:

输入: A[] = {13,14,10,6},K = 2 输出: 2 1 5 9 解释: 对于任何一个索引 I,A[i]都是 B[]除 B[i]之外的所有元素的按位异或。

  1. B[1] ^ B[2] ^ B[3] = 1 ^ 5 ^ 9 = 13 = A[0]
  2. B[0] ^ B[2] ^ B[3] = 2 ^ 5 ^ 9 = 14 = A[1]
  3. B[0] ^ B[1] ^ B[3] = 2 ^ 1 ^ 9 = 10 = A[2]
  4. B[0] ^ B[1] ^ B[2] = 2 ^ 1 ^ 5 = 6 = A[3]

输入: A[] = {3,5,0,2,4},K = 2 T3】输出: 2 4 1 3 5

方法:这个想法是基于这样的观察:计算偶数次的相同值的按位异或是 0

对于任何索引 I, a[I]= b[0]^ b[1]^…b[I-1]^ b[I+1]^…b[n-1] 因此,B[],total XOR = b[0]^ b[1]^…b[I–1]^ b[I]^ b[I+1]…b[n–1]的所有元素的 xor。 因此,B[i] = totalXor ^ A[i]。(因为除了 B[i],每个元素都出现两次)

按照以下步骤解决问题:

下面是上述方法的实现:

C++

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;

// Function to construct an array
// with each element equal to XOR
// of all array elements except
// the element at the same index
void constructArray(int A[], int N,
                    int K)
{
    // Original array
    int B[N];

    // Stores Bitwise XOR of array
    int totalXOR = A[0] ^ K;

    // Calculate XOR of all array elements
    for (int i = 0; i < N; i++)
        B[i] = totalXOR ^ A[i];

    // Print the original array B[]
    for (int i = 0; i < N; i++) {
        cout << B[i] << " ";
    }
}

// Driver Code
int main()
{
    int A[] = { 13, 14, 10, 6 }, K = 2;
    int N = sizeof(A) / sizeof(A[0]);

    // Function Call
    constructArray(A, N, K);

    return 0;
}

Java 语言(一种计算机语言,尤用于创建网站)

// Java program for the above approach
class GFG{

// Function to construct an array
// with each element equal to XOR
// of all array elements except
// the element at the same index
static void constructArray(int A[], int N,
                           int K)
{

    // Original array
    int B[] = new int[N];

    // Stores Bitwise XOR of array
    int totalXOR = A[0] ^ K;

    // Calculate XOR of all array elements
    for(int i = 0; i < N; i++)
        B[i] = totalXOR ^ A[i];

    // Print the original array B[]
    for(int i = 0; i < N; i++)
    {
        System.out.print(B[i] + " ");
    }
}

// Driver Code
public static void main(String[] args)
{
    int A[] = { 13, 14, 10, 6 }, K = 2;
    int N = A.length;

    // Function Call
    constructArray(A, N, K);
}
}

// This code is contributed by divyeshrabadiya07

Python 3

# Python program for the above approach

# Function to construct an array
# with each element equal to XOR
# of all array elements except
# the element at the same index
def constructArray(A, N, K):

    # Original array
    B = [0] * N;

    # Stores Bitwise XOR of array
    totalXOR = A[0] ^ K;

    # Calculate XOR of all array elements
    for i in range(N):
        B[i] = totalXOR ^ A[i];

    # Print the original array B
    for i in range(N):
        print(B[i], end = " ");

# Driver Code
if __name__ == '__main__':
    A = [13, 14, 10, 6];
    K = 2;
    N = len(A);

    # Function Call
    constructArray(A, N, K);

# This code is contributed by Princi Singh

C

// C# program for the above approach
using System;
using System.Collections;
class GFG {

    // Function to construct an array
    // with each element equal to XOR
    // of all array elements except
    // the element at the same index
    static void constructArray(int[] A, int N,
                               int K)
    {

        // Original array
        int[] B = new int[N];

        // Stores Bitwise XOR of array
        int totalXOR = A[0] ^ K;

        // Calculate XOR of all array elements
        for(int i = 0; i < N; i++)
            B[i] = totalXOR ^ A[i];

        // Print the original array B[]
        for(int i = 0; i < N; i++)
        {
            Console.Write(B[i] + " ");
        }
    }

  static void Main() {
    int[] A = { 13, 14, 10, 6 };
    int K = 2;
    int N = A.Length;

    // Function Call
    constructArray(A, N, K);
  }
}

// This code is contributed by divyesh072019

java 描述语言

<script>

// JavaScript program for the above approach

// Function to construct an array
// with each element equal to XOR
// of all array elements except
// the element at the same index
function constructArray(A, N, K)
{
    // Original array
    let B = new Array(N);

    // Stores Bitwise XOR of array
    let totalXOR = A[0] ^ K;

    // Calculate XOR of all array elements
    for (let i = 0; i < N; i++)
        B[i] = totalXOR ^ A[i];

    // Print the original array B[]
    for (let i = 0; i < N; i++) {
        document.write(B[i] + " ");
    }
}

// Driver Code
    let A = [ 13, 14, 10, 6 ], K = 2;
    let N = A.length;

    // Function Call
    constructArray(A, N, K);

// This code is contributed by Surbhi Tyagi.

</script>

Output: 

2 1 5 9

时间复杂度:O(N) T5辅助空间:** O(1)