You are given an array of strings words and a string pref.
Return the number of strings in words that contain pref as a prefix.
A prefix of a string s is any leading contiguous substring of s.
Example 1:
Input: words = ["pay","attention","practice","attend"], pref = "at"
Output: 2
Explanation: The 2 strings that contain "at" as a prefix are: "attention" and "attend".
Example 2:
Input: words = ["leetcode","win","loops","success"], pref = "code"
Output: 0
Explanation: There are no strings that contain "code" as a prefix.
Constraints:
1 <= words.length <= 1001 <= words[i].length, pref.length <= 100words[i]andprefconsist of lowercase English letters.
Solution: Straight forward
We can use std::count_if and std::string::find.
Time complexity: O(n*l)
Space complexity: O(1)
C++
|
1 2 3 4 5 6 7 8 9 |
// Author: Huahua class Solution { public: int prefixCount(vector<string>& words, string pref) { return count_if(begin(words), end(words), [&](const string& w) { return w.find(pref) == 0; }); } }; |
