LeetCode刷题笔记(JAVA)——14. 最长公共前缀

class Solution {
    public String longestCommonPrefix(String[] strs) {
        int length = strs.length;
        int minLength = getMinLength(strs);
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < minLength; ++i) {
            char target = '0';
            Map map = new HashMap<>();//用哈希表给相应的字符计数，如果计数刚好是strs的长度，那么都有相同前缀
            for (String str : strs) {
                map.put(str.charAt(i), map.getOrDefault(str.charAt(i), 0) + 1);
                target = str.charAt(i);
            }
            if (map.get(target) == length) {
                stringBuilder.append(target);
            } else {
                break;
            }
        }
        return stringBuilder.toString();
    }
    public int getMinLength(String[] strs) {
        int result = 201;
        for (String str : strs) {
            result = Math.min(result, str.length());
        }
        return result;
    }
}