14.longest-common-prefix.cpp

/*
 * [14] Longest Common Prefix
 *
 * https://leetcode.com/problems/longest-common-prefix/description/
 *
 * algorithms
 * Easy (32.11%)
 * Total Accepted:    641.9K
 * Total Submissions: 1.9M
 * Testcase Example:  '["flower","flow","flight"]'
 *
 * 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:
 * 
 * 
 * Input: ["flower","flow","flight"]
 * Output: "fl"
 * 
 * 
 * Example 2:
 * 
 * 
 * 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.
 * 
 */
class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        
        if (strs.size() == 0) return "";

        string prefix = "";

        for (int i = 0; i < strs[0].size(); ++i) {

            for (int j = 1; j < strs.size(); ++j) {

                if (i >= strs[j].size() || strs[j][i] != strs[0][i]) {
                    return refix;
                }

                prefix += strs[0][i];
            }
        }

        return prefix;

    }
};