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给你一个数组 items
,其中 items[i] = [typei, colori, namei]
,描述第 i
件物品的类型、颜色以及名称。
另给你一条由两个字符串 ruleKey
和 ruleValue
表示的检索规则。
如果第 i
件物品能满足下述条件之一,则认为该物品与给定的检索规则 匹配 :
ruleKey == "type"
且ruleValue == typei
。ruleKey == "color"
且ruleValue == colori
。ruleKey == "name"
且ruleValue == namei
。
统计并返回 匹配检索规则的物品数量 。
示例 1:
输入: items = [["phone","blue","pixel"],["computer","silver","lenovo"],["phone","gold","iphone"]], ruleKey = "color", ruleValue = "silver"
输出: 1
解释: 只有一件物品匹配检索规则,这件物品是 ["computer","silver","lenovo"] 。
示例 2:
输入: items = [["phone","blue","pixel"],["computer","silver","phone"],["phone","gold","iphone"]], ruleKey = "type", ruleValue = "phone"
输出: 2
解释: 只有两件物品匹配检索规则,这两件物品分别是 ["phone","blue","pixel"] 和 ["phone","gold","iphone"] 。注意,["computer","silver","phone"] 未匹配检索规则。
提示:
1 <= items.length <= 10^4
1 <= typei.length, colori.length, namei.length, ruleValue.length <= 10
ruleKey
等于"type"
、"color"
或"name"
- 所有字符串仅由小写字母组成
思路
这道题很简单,先通过ruleKey
确定物品属性下标,再遍历物品列表,比较对应数据项和ruleValue
是否相等,相等计数器加一,最后返回计数结果就是要求的值,如解法一。
也可通过Array.property.filter
求解,只需三行代码。如解法二。
解题
解法一
/**
* @param {string[][]} items
* @param {string} ruleKey
* @param {string} ruleValue
* @return {number}
*/
var countMatches = function (items, ruleKey, ruleValue) {
let idx = ruleKey === "type" ? 0 : ruleKey === "color" ? 1 : 2;
let count = 0;
for (let i = 0; i < items.length; i++) {
if (items[i][idx] === ruleValue) {
count++;
}
}
return count
};
解法二
/**
* @param {string[][]} items
* @param {string} ruleKey
* @param {string} ruleValue
* @return {number}
*/
var countMatches = function (items, ruleKey, ruleValue) {
let idx = ruleKey === "type" ? 0 : ruleKey === "color" ? 1 : 2;
let filter = (item) => item[idx] === ruleValue;
return items.filter(filter).length;
};