Count Items Matching a Rule — LeetCode 1773 Python Solution

The problem

You are given an array items, where each items[i] = [typei, colori, namei] describes the type, color, and name of the ith item. You are also given a rule represented by two strings, ruleKey and ruleValue.

Example

Input

items = [["phone","blue","pixel"],["computer","silver","lenovo"],["phone","gold","iphone"]], ruleKey = "color", ruleValue = "silver"

Output

1

Explanation

There is only one item matching the given rule, which is ["computer","silver","lenovo"].

Python solution

class Solution:
    def countMatches(self, items: List[List[str]], ruleKey: str, ruleValue: str) -> int:
        i = 0 if ruleKey[0] == 't' else (1 if ruleKey[0] == 'c' else 2)
        return sum(v[i] == ruleValue for v in items)

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1773. Count Items Matching a Rule is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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