Like and unlike

Write code · Medium · §4.2 Pairs as keys

Posts are numbered from 0 to n - 1. presses holds the records of like-button presses in the order they happened. [a, b] means that person a pressed the like button on post b.

At first, every post has 0 likes. If the person who presses the button does not currently like that post, the post gains 1 like. If they currently like that post, their like is canceled and the post loses 1 like.

Complete the function solution, which returns a list of the number of likes left on each post after all the presses, in order from post 0 to post n - 1.

Function

solution(n, presses)

Constraints

n is an integer from 1 to 100,000.
The length of presses is from 1 to 100,000.
The person number a is an integer from 0 to 1,000,000, and the post number b is an integer from 0 to n - 1.

Examples

n	presses	result
`3`	`[[1, 0], [2, 0], [2, 0], [1, 2]]`	`[1, 0, 1]`
`2`	`[[5, 1], [5, 1]]`	`[0, 0]`

Starter code

def solution(n, presses):
    answer = []
    return answer

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