14. Longest Common Prefix [longest common prefix]

description

Write a function to find the longest common prefix string array.
If there is no common prefix, returns an empty string ""

Examples of

ideas

answer

• python

    def longestCommonPrefix(self, strs: List[str]) -> str:
        if len(strs)==0: return ''
        res = strs[0]
        for i in range(len(res)):#长度是逐渐上涨的
            for j in range(1,len(strs)):
                # 如果同一位置字符不一样，或者此时长度超过该字符串
                if i==len(strs[j]) or strs[j][i]!=res[i]:
                    return res[:i]
        return res

• c++

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        if (strs.empty()) return "";
        string res = strs[0];
        for (int i=0; i<res.size(); i++)
            for (int j=1; j<strs.size(); j++)
                if (i==strs[j].size() || res[i]!=strs[j][i])
                    return res.substr(0,i);
        return res;
    }
};