Help me in solving PSEUDOSORT problem why is it neccessary to check a==sortd b

help
,
1

My issue

in the final if conditions why is it necessary a==sorted(b) when the output can be displayed using c

My code

t=int(input())
for _ in range(t):
    n=int(input())
    a=list(map(int,input().split()))
    b=sorted(a)
    c=0
    t=0
    s=sorted(a)
    for i in range(0,n-1):
        if a[i]<=a[i+1]:
            continue
        else:
            c+=1
            t=a[i]
            a[i]=a[i+1]
            a[i+1]=t
    if (c<=1 or c==0) and a==s :
        print("yes")
    else:
        print("no")
    
    '''c=0
    for i in range(0,n-1):
        if a[i]!=b[i]:
            a[i],a[i+1]=b[i],b[i+1]
            c+=1
    if (c==1 or c==0) and a==b:
        print("yes")
    else:
        print("no")
'''

Problem Link: PSEUDOSORT Problem - CodeChef