lintcode: Longest Common Prefix

寻找最长公共前缀

最新推荐文章于 2021-01-31 10:44:05 发布

martin_liang

最新推荐文章于 2021-01-31 10:44:05 发布

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分类专栏： C++/C 算法 lintcode

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本文讨论了如何在一组字符串中找到最长的公共前缀。通过分析示例和代码实现，理解算法逻辑并掌握其实现细节。

Longest Common Prefix

Given k strings, find the longest common prefix (LCP).

Have you met this question in a real interview?

Yes

Example

For strings "ABCD", "ABEF" and "ACEF", the LCP is "A"

For strings "ABCDEFG", "ABCEFG" and "ABCEFA", the LCP is "ABC"

Tags

class Solution {
public:    
    /**
     * @param strs: A list of strings
     * @return: The longest common prefix
     */
    string longestCommonPrefix(vector<string> &strs) {
        // write your code here
        
        if (strs.size() == 0)
            return ""; // 这个条件判断非常重要
        
        int compLen = INT_MAX;
        for (int i=0; i<strs.size(); i++)
            compLen = min((int)strs[i].size(), compLen);
            
        string retStr = "";
        for (int j=0; j<compLen; j++)
        {
            char pivot = strs[0][j];
            for (int i=1; i<strs.size(); i++)
            {
                if (strs[i][j] != pivot)
                {
                    if (j > 0)
                    {
                        return strs[i].substr(0, j);
                    }
                    else
                    {
                        return "";
                    }
                }
            }
        }
        return strs[0].substr(0, compLen);
    }
};