1002. Find Common Characters

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題目敘述

Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order.

Example 1

Input: words = [“bella”,“label”,“roller”] Output: [“e”,“l”,“l”]

Example 2

Input: words = [“cool”,“lock”,“cook”] Output: [“c”,“o”]

解題思路

Solution

import java.util.ArrayList;
import java.util.List;

class Solution {
    public List<String> commonChars(String[] words) {
        int len = words.length;
        int[][] freq = new int[len][26];
        for (int i = 0; i < len; i++) {
            for (char c : words[i].toCharArray()) {
                freq[i][c - 'a']++;
            }
        }

        List<String> result = new ArrayList<>();
        for (int i = 0; i < 26; i++) {
            int min = Integer.MAX_VALUE;
            for (int j = 0; j < len; j++) {
                min = Math.min(min, freq[j][i]);
                if(min == 0)  break;
            }
            for (int j = 0; j < min; j++) {
                result.add(String.valueOf((char) (i + 'a')));
            }
        }

        return result;
    }
}