# 1773. 统计匹配检索规则的物品数量

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 == $type_i$ 。
ruleKey == “color” 且 ruleValue == $color_i$ 。
ruleKey == “name” 且 ruleValue == $name_i$ 。
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：

$1 <= items.length <= 10^4$
$1 <= type_i.length, color_i.length, name_i.length, ruleValue.length <= 10$
ruleKey 等于 “type”、“color” 或 “name”
所有字符串仅由小写字母组成

# 题解

class Solution {
public:
    int countMatches(vector<vector<string>>& items, string ruleKey, string ruleValue) {
        int flag;
        int ans=0;
        if(ruleKey=="type")
            flag=0;
        else if(ruleKey=="color")
            flag=1;
        else
            flag=2;
        for(int i=0;i<items.size();i++){
            if(items[i][flag]==ruleValue)
                ans++;
        }
        return ans;
    }
};