28. Implement strStr()

Problem

https://leetcode.com/problems/implement-strstr/

Implement strStr().

Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Solution

return haystack.indexOf(needle)

or slower

return haystack.search(needle)

plain search

/**
 * @param {string} haystack
 * @param {string} needle
 * @return {number}
 */
var strStr = function(haystack, needle) {
    let len = haystack.length - needle.length + 1
    for (let i = 0; i < len; i += 1) {
        let j, k
        for (j = i, k = 0; k < needle.length; j += 1, k += 1) {
            if (haystack[j] !== needle[k]) {
                break
            }
        }
        if (k === needle.length) {
            return i
        }
    }
    return -1
};