Write a function to find the longest common prefix string amongst an array of strings.
https://leetcode.com/problems/longest-common-prefix/description/
给定输入是一个字符串数组,输出元素最长起始公共串。如{"aab","ac","aac"},则输出"a"
思路:首先取第一个元素,不断对其取subString(缩小串长度)与后面的元素起始比较,用了indexOf这个方法,返回0则说明它是这个String的起始子串
public String longestCommonPrefix(String[] strs) { if(strs ==null || strs.length == 0){ return ""; } String maxLengthStr = strs[0]; for(int i=1;i<strs.length;i++){ while (strs[i].indexOf(maxLengthStr)!=0){ maxLengthStr = maxLengthStr.substring(0,maxLengthStr.length() -1); } } return maxLengthStr; }
当然也可以用startsWith
public String longestCommonPrefix(String[] strs) { if(strs ==null || strs.length == 0){ return ""; } String maxLengthStr = strs[0]; for(int i=1;i<strs.length;i++){ while (!strs[i].startsWith(maxLengthStr)){ maxLengthStr = maxLengthStr.substring(0,maxLengthStr.length()-1); } } return maxLengthStr; }