1662. Check If Two String Arrays are Equivalent

Problem

Given two string arrays word1 and word2, return** true if the two arrays represent the same string, and false otherwise.**

A string is represented by an array if the array elements concatenated in order forms the string.

  Example 1:

Input: word1 = ["ab", "c"], word2 = ["a", "bc"]
Output: true
Explanation:
word1 represents string "ab" + "c" -> "abc"
word2 represents string "a" + "bc" -> "abc"
The strings are the same, so return true.

Example 2:

Input: word1 = ["a", "cb"], word2 = ["ab", "c"]
Output: false

Example 3:

Input: word1  = ["abc", "d", "defg"], word2 = ["abcddefg"]
Output: true

  Constraints:

• 1 <= word1.length, word2.length <= 103

• 1 <= word1[i].length, word2[i].length <= 103

• 1 <= sum(word1[i].length), sum(word2[i].length) <= 103

• word1[i] and word2[i] consist of lowercase letters.

Solution

/**
 * @param {string[]} word1
 * @param {string[]} word2
 * @return {boolean}
 */
var arrayStringsAreEqual = function(word1, word2) {
    var i = 0;
    var m = 0;
    var j = 0;
    var n = 0;
    while (i < word1.length && j < word2.length) {
        if (word1[i][m] !== word2[j][n]) return false;
        if (m === word1[i].length - 1) {
            i += 1;
            m = 0;
        } else {
            m += 1;
        }
        if (n === word2[j].length - 1) {
            j += 1;
            n = 0;
        } else {
            n += 1;
        }
    }
    return i === word1.length && j === word2.length;
};

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(1).