[题目地址]https://leetcode.com/problems/longest-common-prefix/
题目概要:
Write a function to find the longest common prefix string amongst an array of strings.
在一个String的列表中找到最长的相同的前缀String.
思路1:
- 先将String列表进行排序, 然后只需要找出第一个String和最后一个String相同的前缀即可.
public class Solution {
public String longestCommonPrefix(String[] strs) {
if (strs == null || strs.length == 0) {
return "";
}
Arrays.sort(strs);
StringBuilder result = new StringBuilder();
char[] first = strs[0].toCharArray();
char[] last = strs[strs.length - 1].toCharArray();
for (int i = 0; i < first.length; i++) {
if (last.length > i && last[i] == first[i]) {
result.append(first[i]);
} else {
return result.toString();
}
}
return result.toString();
}
}
思路2:
- 取第一个String作为起始值，和下一个String进行比较，直到找到相同的前缀，遍历所有剩余的String.
public class Solution {
public String longestCommonPrefix(String[] strs) {
if (strs == null || strs.length == 0) {
return "";
}
String result = strs[0];
for (int i = 1; i < strs.length; i++) {
while (strs[i].indexOf(result) != 0) {
result = result.substring(0, result.length() - 1);
}
}
return result;
}
}
