/** * 1002. Find Common Characters * https://leetcode.com/problems/find-common-characters/submissions/ * Given an array A of strings made only from lowercase letters, * return a list of all characters that show up in all strings within the list (including duplicates). * For example, if a character occurs 3 times in all strings but not 4 times, you need to include that character three times in the final answer. You may return the answer in any order. Example 1: Input: ["bella","label","roller"] Output: ["e","l","l"] * */ class Solution { fun commonChars(A: Array<String>): List<String> { val result = ArrayList<String>() val map = HashMap<Char, IntArray>() for (i in 0..(A.size - 1)) { for (c in A[i]) { if (!map.containsKey(c)) { map.put(c, IntArray(A.size)) } //array数组保存为:出现过的char在每一个A的子数组中出现的次数,顺序对应着A的子数组 //如a在"bella","label","roller",对应为[1,1,0] val array = map.get(c)!! array[i]++ map.put(c, array) } } map.forEach { key, charCountArr -> var canInsertFlag = 0 for (v in charCountArr) { canInsertFlag += v } var canInsert = canInsertFlag >= A.size if (canInsert) { charCountArr.sort() var insertCount = charCountArr[0] for (j in 0..(insertCount - 1)) { result.add(key.toString()) } } } return result } }