面试经典150题——Day20

一、题目

14. Longest Common Prefix

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: strs = [“flower”,“flow”,“flight”]
Output: “fl”
Example 2:

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

Constraints:

1 <= strs.length <= 200
0 <= strs[i].length <= 200
strs[i] consists of only lowercase English letters.

题目来源： leetcode

二、题解

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        int n = strs.size();
        int count = strs[0].length();
        for(int i = 0;i < n - 1;i++){
            int len1 = strs[i].length();
            int len2 = strs[i + 1].length();
            int tmp = 0;
            for(int j = 0;j < len1 && j < len2;j++){
                if(strs[i][j] == strs[i + 1][j]) tmp++;
                else break;
            }
            count = min(count,tmp);
        }
        string res = "";
        for(int i = 0;i < count;i++) res += strs[0][i];
        return res;
    }
};
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