花花酱 LeetCode 1773. Count Items Matching a Rule

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.

The ith item is said to match the rule if one of the following is true:

• ruleKey == "type" and ruleValue == typei.
• ruleKey == "color" and ruleValue == colori.
• ruleKey == "name" and ruleValue == namei.

Return the number of items that match the given rule.

Example 1:

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"].

Example 2:

Input: items = [["phone","blue","pixel"],["computer","silver","phone"],["phone","gold","iphone"]], ruleKey = "type", ruleValue = "phone"
Output: 2
Explanation: There are only two items matching the given rule, which are ["phone","blue","pixel"] and ["phone","gold","iphone"]. Note that the item ["computer","silver","phone"] does not match.

Constraints:

• 1 <= items.length <= 104
• 1 <= typei.length, colori.length, namei.length, ruleValue.length <= 10
• ruleKey is equal to either "type", "color", or "name".
• All strings consist only of lowercase letters.

Solution: Brute Force

Time complexity: O(n)
Space complexity: O(1)