challenges-116.js

// // 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.

//solution

function countMatches(items, ruleKey, ruleValue) {
  const keyToIndex = { type: 0, color: 1, name: 2 };
  const index = keyToIndex[ruleKey];
  const filteredItems = items.filter((item) => item[index] === ruleValue);
  return filteredItems.length;
}

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

console.log(countMatches(items, ruleKey, ruleValue)); // Output: 1