Pseudo Sorted Array Codechef Solution

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Pseudo Sorted Array Codechef Solution

An array A of length N is said to be pseudo-sorted if it can be made non-decreasing after performing the following operation at most once.

Choose an i such that 1≤i≤N−1 and swap Ai and Ai+1
Given an array A, determine if it is pseudo-sorted or not.

Input Format
The first line contains a single integer T – the number of test cases. Then the test cases follow.
The first line of each test case contains an integer N – the size of the array A.
The second line of each test case contains N space-separated integers A1,A2,…,AN denoting the array A.
Output Format
For each testcase, output YES if the array A is pseudo-sorted, NO otherwise.

You may print each character of YES and NO in uppercase or lowercase (for example, yes, yEs, Yes will be considered identical).

Constraints
1≤T≤1000
2≤N≤105
1≤Ai≤109
Sum of N over all test cases do not exceed 2⋅105
Sample Input 1
3
5
3 5 7 8 9
4
1 3 2 3
3
3 2 1
Sample Output 1
YES
YES
NO
Explanation
Test case 1: The array is already sorted in non-decreasing order.

Test case 2: We can choose i=2 and swap A2 and A3. The resulting array will be [1,2,3,3], which is sorted in non-decreasing order.

Test case 3: It can be proven that the array cannot be sorted in non-decreasing order in at most one operation.

SOLUTION

Program: Pseudo Sorted Array Codechef Solution in Python

for _ in range(int(input())):
    n=int(input())
    t=0
    tmp=0
    l=list(map(int,input().split()))
    for i in range(n):
        if l[i-1]>l[i] and i>=1:
            tmp=l[i-1]
            l[i-1]=l[i]
            l[i]=tmp
            if l[i-2] > l[i-1] and i>=2:
                t+=2
            else:
                t+=1
    if t<2:
        print("YES")
    else:
        print("NO")

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Pseudo Sorted Array Codechef Solution

Pseudo Sorted Array Codechef Solution

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