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")Related:
