LeetCode 14 最長公共前綴（難度：Easy）

題意大意：給出一個字符串數組，找出所有字符串的最長公共前綴。如果沒有公共前綴，返回字符串 ：“”

 

Write a function to find the longest common prefix string amongst an array of strings.

If there is no common prefix, return an empty string "".

 

Example 1:

Input: ["flower","flow","flight"]
Output: "fl"

Example 2:

Input: ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.

Note:

All given inputs are in lowercase letters a-z.

 

package pers.leetcode;

/**
 * LeetCode 14 Longest Common Prefix
 * 難易程度: Easy
 *
 * @author jinghui.zhu
 * @date 2019/4/26 10:18
 */
public class LongestCommonPrefix {

    public static void main(String[] args) {
        String[] strs = {"flower", "flow", "flight"};
        String commonPrefix = longestCommonPrefix(strs);
        System.out.println("最長公共前綴是: " + commonPrefix);
    }

    public static String longestCommonPrefix(String[] strs) {
        if (strs == null || strs.length == 0) {
            return "";
        }
        for (int i = 0; i < strs[0].length(); i++){
            char c = strs[0].charAt(i);
            for (int j = 1; j < strs.length; j++){
                if (i == strs[j].length() || strs[j].charAt(i) != c){
                    return strs[0].substring(0, i);
                }
            }
        }
        return strs[0];
    }
}