find_the_longest_common_prefix.md

Find the Longest Common Prefix

Find the Longest Common Prefix

To find the longest common prefix among a set of strings, iterate through the strings character by character and check if they match.

Algorithm:

1. Sort the array of strings.
2. Compare the first and the last string character by character.
3. The characters that match are the common prefix.
4. Return the common prefix.

Example:

function longestCommonPrefix(strs) {
    if (strs.length === 0) return '';
    strs.sort();
    let first = strs[0], last = strs[strs.length - 1];
    let i = 0;
    while (i < first.length && first[i] === last[i]) {
        i++;
    }
    return first.substring(0, i);
}

// Example usage
console.log(longestCommonPrefix(['flower', 'flow', 'flight'])); // Output: 'fl'
console.log(longestCommonPrefix(['dog', 'racecar', 'car'])); // Output: ''

This method has a time complexity of O(n log n), where n is the number of strings.

Tags: basic, JavaScript, Strings, Algorithm