Leetcode 14. Longest Common Prefix

Description: 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 ""

Link: 14. Longest Common Prefix

Examples:

Example 1:
Input: strs = ["flower","flow","flight"]
Output: "fl"

Example 2:
Input: strs = ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.

思路:计算得到最短的string的长度，然后在这个长度内遍历每个字母是否common for all strings.

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if not strs: return ''
        min_len = min([len(s) for s in strs])
        res = ''
        for i in range(min_len):
            if len(set([s[i] for s in strs])) == 1:
                res += strs[0][i]
            else:
                break
        return res

我们也可以不去计算最短的string长度，而是直接任意选一个string，然后用try, except IndexError 来处理。

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if not strs: return ''
        res = ''
        for i in range(len(strs[0])):
            try: 
                if len(set([s[i] for s in strs])) == 1:
                    res += strs[0][i]
                else:
                    return res
            except IndexError:
                return res
        return res

日期: 2021-04-17