描述
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.
Note:
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.
解析
根据题意，只需要将字符串 type 看作索引 0 ，color 看作索引 1 ，name 看作索引 2 ，那么在遍历二维数组 items 的时候，只需要和每个一维数组的对应索引的值和 ruleKey 进行比较即可，相等则计数，最后返回计数结果。
解答
class Solution(object):
def countMatches(self, items, ruleKey, ruleValue):
"""
:type items: List[List[str]]
:type ruleKey: str
:type ruleValue: str
:rtype: int
"""
k = 0
c = 0
if ruleKey=="type":
k = 0
elif ruleKey=="color":
k = 1
elif ruleKey=="name":
k = 2
for items in items:
if items[k] == ruleValue:
c += 1
return c
运行结果
Runtime: 196 ms, faster than 100.00% of Python online submissions for Count Items Matching a Rule.
Memory Usage: 21.1 MB, less than 100.00% of Python online submissions for Count Items Matching a Rule.
原题链接：https://leetcode.com/problems/count-items-matching-a-rule/