14. Longest Common Prefix

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.

/**
 * @param {string[]} strs
 * @return {string}
 */
var longestCommonPrefix = function(strs) {
    if (!strs.length) {
        return '';
    }
    const len = strs[0].length;
    let i = 0;
    for (; i < len; i++) {
        if (!isSame(strs, i)) {
            break;
        };
    }
    return strs[0].substring(0, i);

    function isSame(strs, idx) {
        for (let j = 0; j < strs.length - 1; j++) {
            if (strs[j][idx] !== strs[j + 1][idx]) {
                return false;
            }
        }
        return true;
    }
};

/**
 * @param {string[]} strs
 * @return {string}
 */
var longestCommonPrefix = function(strs) {
    if (!strs.length) {
        return '';
    }
    if (strs.length === 1) {
        return strs[0];
    }
    let minWord = strs[0];
    for (let n = 1; n < strs.length; n++) {
        if (strs[n].length > minWord.length) {
            minWord = strs[n];
        }
    }
    const len = minWord.length;
    let i = 0;
    for (; i < len; i++) {
        if (!isSame(strs, i)) {
            break;
        };
    }
    return minWord.substring(0, i);

    function isSame(strs, idx) {
        for (let j = 0; j < strs.length - 1; j++) {
            if (strs[j][idx] !== strs[j + 1][idx]) {
                return false;
            }
        }
        return true;
    }
};