一, 题目
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.
二, 解题思路
1, 获取数组的第一个元素 firstStr 作为比较的对象;
2, 以 firstStr 的长度作为条件设定 while 循环;
3, 从数组第二个元素开始遍历数组, 判断每个元素是否已 firstStr 作为前缀;
4, 如果不是, 则截掉 firstStr 最后一个字符, 再重新遍历数组进行比较.
三, 代码实现
- public String longestCommonPrefix(String[] strs) {
- if (strs.length == 0) { // 当数组长度为 0 时, 返回空
- return "";
- } else if (strs.length == 1) { // 当数组只有一个元素时, 则返回该元素
- return strs[0];
- } else {
- String firstStr = strs[0];
- while (firstStr.length() != 0) {
- for (int i = 1; i < strs.length; i++) {
- if (strs[i].startsWith(firstStr)) {
- if (i == strs.length -1) {
- return firstStr;
- }
- continue;
- } else {
- // 从后往前一个一个截取
- firstStr = firstStr.substring(0, firstStr.length() - 1);
- break;
- }
- }
- }
- }
- return "";
- }
来源: http://www.bubuko.com/infodetail-3073063.html