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# Python program to find number of likes and dislikes

Alice and Bob made a list of topics and both of them voted if they like or dislike the topic. They wrote 0 to denote dislike and 1 to denote like. The task is to count the number of topics that both of them like or dislike. Examples:

Input: alice = “010101” bob = “101101” Output: 3 alice and bob both like 4th and 6th topics and dislike the 5th topic. Hence, the output is 3. Input: alice = “111111” bob = “000000” Output: 0 There are no common likes or dislikes between alice and bob. Hence, the output is 0.

Input: alice = “110000” bob = “110011” Output: 4 alice and bob both like 1st and 2nd topics and dislike 3rd and 4th topics. Hence, the result is 4.

Approach:

• First, we have to iterate through each character of the string consisting of the likes and dislikes of alice.
• Then, we have to compare it with the corresponding entry of the string consisting of the likes and dislikes of bob.
• Finally, we will count the number of similar entries and print.

Below is the implementation.

## Python3

 `# function to obtain no ` `# of topics both alice and ` `# bob like ` `def` `commontopics(alice, bob): ` ` `  ` ``# initiate count with 0 ` ` ``count ``=` `0` ` `  ` ``# iterating through alice ` ` ``for` `i ``in` `range``(``0``,``len``(alice)): ` `  `  `  ``# comparing with corresponding ` `  ``# bob entry ` `  ``if` `alice[i] ``=``=` `bob[i]: ` `   `  `   ``# counting similar entries ` `   ``count ``+``=` `1` `   `  ` ``# printing the count   ` ` ``print``(count) `   `#main function ` `def` `main(): ` ` `  ` ``commontopics(``"010101"``, ``"101101"``) ` ` ``commontopics(``"111111"``, ``"000000"``) ` ` ``commontopics(``"110000"``, ``"110011"``) `   ` `  `# driver code ` `if` `__name__ ``=``=` `"__main__"``: ` ` ``main() `   `# This code is contributed by SrujayReddy `

Output:

```3
0
4```

The Time and Space Complexity for all the methods are the same:

Time Complexity: O(n)

Space Complexity: O(n)

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