No.14 Longest Common Prefix

No.14 Longest Common Prefix

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

求一组string的最长公共前缀
想法：找到最短的那个，然后依次对比

 

典型的字符串操作，从前向后比较即可

 

#include "stdafx.h"
#include <string>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

class Solution
{
public:
    string longestCommonPrefix(vector<string> &strs)
    {//求一组string的最长公共前缀
     //想法：找到最短的那个，然后依次对比
        int size = strs.size();
        string res("");
        if(size == 0)
            return res;

        int shortestCount = strs[0].size();//记录最短的
        for(int i=1; i<size; i++)
        {
            if(strs[i].size() < shortestCount)
                shortestCount = strs[i].size();
        }

        //从前向后比较shortestCount位
        for(int i=0; i<shortestCount; i++)
        {
            auto tmp = strs[0][i];
            for(int j=1; j<size; j++)
            {
                if(strs[j][i] != tmp)
                    return res;
            }
            res += tmp;
        }
        return res;
    }
};

int main()
{
    Solution sol;
    string data[] = {"a","abc","ad"};
    vector<string> test(data,data+3);
    cout << sol.longestCommonPrefix(test)<<endl;

    string data1[] = {"ad","abc","ad",""};
    vector<string> test1(data1,data1+4);
    cout << sol.longestCommonPrefix(test1)<<endl;
}