[Leetcode] Longest Common Prefix

Longest Common Prefix 题解

题目来源：https://leetcode.com/problems/longest-common-prefix/description/

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Description

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

Solution

class Solution {
private:
    size_t getShortestStrIdx(vector<string>& strs) {
        size_t res = 0;
        auto minLen = strs[0].length();
        auto size = strs.size();
        decltype(minLen) tempLen;
        for (size_t i = 1; i < size; i++) {
            tempLen = strs[i].length();
            if (tempLen < minLen) {
                minLen = tempLen;
                res = i;
            }
        }
        return res;
    }
public:
    string longestCommonPrefix(vector<string>& strs) {
        if (strs.empty())
            return "";
        string res = strs[getShortestStrIdx(strs)];
        auto size = strs.size();
        for (size_t i = 0; i < size; i++) {
            string::size_type len = 0;
            while (len < res.length() && len < strs[i].length()) {
                if (res[len] == strs[i][len])
                    len++;
                else
                    break;
            }
            if (len == 0)
                return "";
            if (len < res.length())
                res.resize(len);
        }
        return res;
    }
};

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解题描述

这道题题意是对给定的字符串数组，求所有字符串的最长公共前缀。我的算法是，先找到所有字符串中最短的一个，在用这个字符串作为结果初始值去跟其它所有字符串匹配。每次都从第0个字符开始，一旦第0个字符不匹配直接返回空串，反之则匹配到不匹配为止，每次刷新结果串的长度。