Longest common prefix

A function to find the longest common prefix string amongst an array of strings.

Go

Time complexity: $O(n * l)$ - n is a length of a strings array and l is a largest length of a word
Auxiliary space: $O(n)$ - n is a number of all characters in all strings

func longestCommonPrefix(strs []string) string {
    var isMaxCommonPrefix bool = false;

    var commonPrefix string = "";

    firstWord := strs[0];

    for charIdx := 0; isMaxCommonPrefix == false; charIdx++ {
        // maxCommonPrefix is found
        if (isMaxCommonPrefix) {
            break;
        }

        for wordIdx := 0; wordIdx < len(strs); wordIdx++ {
            // next word does not have next character
            if (charIdx == len(strs[wordIdx])) {
                isMaxCommonPrefix = true;
                break;
            }

            // prefix does not match with next word
            if (firstWord[charIdx] != strs[wordIdx][charIdx]) {
                isMaxCommonPrefix = true;
                break;
            }
        }

        // no exceptions thrown
        if (isMaxCommonPrefix == false) {
            commonPrefix += string(firstWord[charIdx]);
        }
    }

    return commonPrefix;
}

thoughtbook

Longest common prefix

Go