Leetcode 438. Find All Anagrams in a String (Easy) (cpp)
阿新 • • 發佈:2019-01-27
Leetcode 438. Find All Anagrams in a String (Easy) (cpp)
Tag: Hash Table
Difficulty: Easy
/* 438. Find All Anagrams in a String (Easy) Given a string s and a non-empty string p, find all the start indices of p's anagrams in s. Strings consists of lowercase English letters only and the length of both strings s and p will not be larger than 20,100. The order of output does not matter. Example 1: Input: s: "cbaebabacd" p: "abc" Output: [0, 6] Explanation: The substring with start index = 0 is "cba", which is an anagram of "abc". The substring with start index = 6 is "bac", which is an anagram of "abc". Example 2: Input: s: "abab" p: "ab" Output: [0, 1, 2] Explanation: The substring with start index = 0 is "ab", which is an anagram of "ab". The substring with start index = 1 is "ba", which is an anagram of "ab". The substring with start index = 2 is "ab", which is an anagram of "ab". */ class Solution { public: vector<int> findAnagrams(string s, string p) { if (s.length() < p.length()) { return{}; } vector<int> res; int mapping[26] = { 0 }; for (char cha : p) { mapping[cha - 'a']++; } int cnt = p.size(), i = 0, j = 0; while (j < s.length()) { if (j - i == p.length() && mapping[s[i++] - 'a']++ >= 0) { cnt++; } if (--mapping[s[j++] - 'a'] >= 0) { cnt--; } if (cnt == 0) { res.push_back(i); } } return res; } };