Description

LINK:

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:

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Input: ["flower","flow","flight"]
Output: "fl"

Example 2:

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

Note:

All given inputs are in lowercase letters a-z.

Solution

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static int _ = []() {
    ios::sync_with_stdio(false);
    cin.tie();
    return 0;
}();

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        if (strs.empty() || strs[0].empty()) return "";
        if (strs.size() == 1) return strs[0];
        int len = 0;
        char ch = strs[0][0];
        while (true) {
            int i;
            for (i = strs.size() - 1; i > 0 && strs[i][len] == ch; i--);
            if (i == 0) ch = strs[0][++len];
            else break;
        }
        return strs[0].substr(0, len);
    }
};

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