LeetCode in Kotlin
438. Find All Anagrams in a String
Medium
Given two strings s and p, return an array of all the start indices of p’s anagrams in s. You may return the answer in any order.
An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
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”.
Constraints:
1 <= s.length, p.length <= 3 * 104sandpconsist of lowercase English letters.
Solution
class Solution {
fun findAnagrams(s: String, p: String): List<Int> {
val map = IntArray(26)
for (i in 0 until p.length) {
map[p[i] - 'a']++
}
val res: MutableList<Int> = ArrayList()
var i = 0
var j = 0
while (i < s.length) {
val idx = s[i] - 'a'
// add the new character
map[idx]--
// if the length is greater than windows length, pop the left charcater in the window
if (i >= p.length) {
map[s[j++] - 'a']++
}
var finish = true
for (k in 0..25) {
// if it is not an anagram of string p
if (map[k] != 0) {
finish = false
break
}
}
if (i >= p.length - 1 && finish) {
res.add(j)
}
i++
}
return res
}
}