Coding-Problems-Solutions/Clevertap Backend Engineer Hiring Challenge hackerearth question 2 at main · tejad245/Coding-Problems-Solutions · GitHub

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Question 2:
Timestamp
CleverTap’s users can access the platform via a website and a mobile app. Every time the user visits the website/mobile app, we store a timestamp of the visit.

Most of our users access the platform via the website only, however, there are a few who use both mediums to access it. Given the visit history for a particular user, our product manager would like to know how many times the user switched devices.

Example 1:
9 am, 1 Apr - Website #1
7 pm, 2 Apr - Website #2
8 pm, 2 Apr - Website #3
8 am, 7 Apr - App #4
9 am, 7 Apr - Website #5

In the example above, the user switched devices twice - once from the Website to the App (#3 to #4), and then from the App back to the Website (#4 to #5).

Example 2:
1 am, 10 Apr - App #1
7 pm, 18 Apr - Website #2
8 pm, 28 Apr - Website #3
8 am, 29 Apr - App #4
9 am, 29 Apr - Website #5

In this example, the user switched devices thrice - once from the App to the Website (#1 to #2), and then from the Website to the App (#3 to #4), and finally from the App to the Website (#4 to #5).

Function Description
You will be given the timestamps of website visits and the app visits. You’ll have to write a function computeDeviceCrossovers in the editor below. The function must return an integer denoting the number of times the given user has switched devices.

computeDeviceCrossovers has the following parameters:

websiteVisits:  an array of n integers, where each websiteVisits[i] is the timestamp at which a user visited the website (sorted in ascending order)
appVisits:  an array of m integers, where each appVisits[j] is the timestamp at which a user visited the app (sorted in ascending order)
Constraints

1≤n≤10,000
1≤m≤10,000
Testcase

A number n - followed by n lines - each line denoting website visit timestamp
A number m, following by m lines - each line denoting app visit timestamp

#code

def computeDeviceCrossovers (n, websiteVisits, m, appVisits):
    if(n==0 or n==0):
        return 0
    else:
        l=[]
        l.extend(websiteVisits)
        l.extend(appVisits)
        l.sort()
        d={}
        c=0
        for i in range(0,len(l)):
            if(l[i] in websiteVisits):
                d[l[i]]='w'
            if(l[i] in appVisits):
                d[l[i]]='a'
        newl=list(d.values())
        #print(newl)
        for i in range(0,len(newl)):
            if(i==0):
                prev=newl[i]
            else:
                cur=newl[i]
                if(prev!=cur):
                    c=c+1
                prev=cur
        return c


n = int(input())
websiteVisits = []
appVisits = []
for i in range(0,n):
    temp = int(input())
    websiteVisits.append(temp)
m = int(input())
for i in range(0,m):
    temp = int(input())
    appVisits.append(temp)

out_ = computeDeviceCrossovers(n, websiteVisits, m, appVisits)
print(out_)