LeetCode-Easy部分中标签为String 14. Longest Common Prefix

原题

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

举例：

"abab","aba","" 返回""

"abab","aba" 返回"aba"

代码分析

求各个字符串的最大公共前缀。先求出前2个最大公共前缀 cstr，然后拿它在之后字符依次比较，有一个不是，则丢弃 cstr 的最后一个字符。

实现代码

public string LongestCommonPrefix(string[] strs)
{
if(strs==null || strs.Length==0)
return "";
if (strs.Length == 1)
return strs[0];

string longestPrefix = firstTwoStrs(strs);
if (longestPrefix.Length == 0)
return "";
int i=2;
while(i < strs.Length)
{
if (strs[i].IndexOf(longestPrefix) != 0)
{
longestPrefix =
longestPrefix.Substring(0, longestPrefix.Length - 1);
i = 1;
if (longestPrefix.Length == 0)
return "";
}
i++;
}
return longestPrefix;
}

//头两个字符串的公共串
private string firstTwoStrs(string[] strs)
{
if (strs.Length < 2) return "";
StringBuilder sb = new StringBuilder();
int len = strs[0].Length < strs[1].Length ? strs[0].Length : strs[1].Length;
for(int i=0;i<len;i++)
{
if (strs[0][i] == strs[1][i])
sb.Append(strs[0][i]);
else
break;
}
return sb.ToString();
}

更多string题目

http://blog.csdn.net/daigualu/article/details/69566863