从其对和数组构造一个数组

给定一个成对和数组和原始数组的大小(n)，构造原始数组。
数组的成对和数组是包含有序形式的所有对的和的数组。例如，arr [] = {6，8，3，4}的成对和数组为{14，9，10，11，12，7}。
通常，arr [0..n-1]的成对和数组为{arr [0] + arr [1]，arr [0] + arr [2]，……。，arr [1] + arr [ 2]，arr [1] + arr [3]，……。，arr [2] + arr [3]，arr [2] + arr [4]，…。，arr [n-2] + arr [n -1}。
“给出一个成对和数组，构造原始数组。”
强烈建议您最小化浏览器，然后自己尝试。
假设给定的数组为“ pair []”，并且原始数组中有n个元素。如果我们看几个例子，我们可以看到arr [0]是pair [0] + pair [1] – pair [n-1]的一半。请注意，对[0] +对[1] –对[n-1]的值是(arr [0] + arr [1])+(arr [0] + arr [2])–(arr [1 ] + arr [2])。
一旦我们评估了arr [0]，我们就可以通过减去arr [0]来评估其他元素。例如，可以通过从对[0]中减去arr [0]来评估arr [1]，可以从对[1]中减去arr [0]来评估arr [2]。
以下是上述想法的实现。

C++

#include 
using namespace std;
 
// Fills element in arr[] from its pair sum array pair[].
// n is size of arr[]
void constructArr(int arr[], int pair[], int n)
{
    arr[0] = (pair[0]+pair[1]-pair[n-1]) / 2;
    for (int i=1; i

---

Java

import java.io.*;
 
class PairSum {
     
    // Fills element in arr[] from its pair sum array pair[].
    // n is size of arr[]
    static void constructArr(int arr[], int pair[], int n)
    {
        arr[0] = (pair[0]+pair[1]-pair[n-1]) / 2;
        for (int i=1; i

---

Python3

# Fills element in arr[] from its
# pair sum array pair[].
# n is size of arr[]
 
def constructArr(arr,pair,n):
    arr [0] = (pair[0]+pair[1]-pair[n-1])//2
    for i in range(1,n):
        arr[i] = pair[i-1]-arr[0]
 
# Driver code
if __name__=='__main__':
    pair = [15, 13, 11, 10, 12, 10, 9, 8, 7, 5]
    n =5
    arr = [0]*n
    constructArr(arr,pair,n)
    for i in range(n):
        print(arr[i],end =" ")
 
# This code is contributed by
# Shrikant13

C#

// C# program to construct an
// array from its pair-sum array
using System;
 
class PairSum
{
    // Fills element in arr[] from its
    // pair sum array pair[].
    // n is size of arr[]
    static void constructArr(int []arr, int []pair,
                                             int n)
    {
        arr[0] = (pair[0] + pair[1] - pair[n - 1]) / 2;
        for (int i = 1; i < n; i++)
            arr[i] = pair[i - 1] - arr[0];
    }
     
    // Driver program to test above function
    public static void Main()
    {
        int []pair = {15, 13, 11, 10, 12,
                         10, 9, 8, 7, 5};
        int n = 5;
        int []arr = new int[n];
        constructArr(arr, pair, n);
        for (int i = 0; i < n; i++)
            Console.Write(arr[i] + " ");    
    }
}
 
// This code is contributed by nitin mittal

Javascript

 
// Fills element in arr[] from
// its pair sum array pair[].
// n is size of arr[]
function constructArr(arr, pair, n)
{
    arr[0] = Math.floor((pair[0]+pair[1]-pair[n-1]) / 2);
    for (let i=1; i<n; i++)
        arr[i] = pair[i-1]-arr[0];
}
 
// Driver program to test above function
 
    let pair = [15, 13, 11, 10, 12, 10, 9, 8, 7, 5];
    let n = 5;
    let arr = new Array(n);
    constructArr(arr, pair, n);
    for (let i = 0; i < n; i++)
        document.write(arr[i] + " ");
 
 
// This code is contributed by Surbhi Tyagi.
 

输出：

8 7 5 3 2