Longest Common Prefix

Longest Common Prefix

Problem Summary

Given an array of strings strs, find and return the longest common prefix — the longest string that appears as a leading substring in every string of the array.

If the strings share no common starting characters, return an empty string "".

• The array contains between 1 and 200 strings.
• Each string has a length between 0 and 200 characters (strings can be empty).
• Non-empty strings consist only of lowercase English letters.

Techniques

• Array
• String
• Trie

Solution

function longestCommonPrefix(strs: string[]): string {
    strs.sort()

    const first = strs[0] ?? ""
    const last = strs[strs.length - 1] ?? ""
    const minStringLength = Math.min(first.length, last.length)
    let i = 0
    let common = ""

    while (first.charAt(i) === last.charAt(i) && i < minStringLength) {
        common = common + first.charAt(i)
        i++
    }

    return common
}

console.log(longestCommonPrefix(["flower","flow","flight"]))
console.log(longestCommonPrefix(["dog","racecar","car"]))