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1754. Largest Merge Of Two Strings

Difficulty Topics

Description

You are given two strings word1 and word2. You want to construct a string merge in the following way: while either word1 or word2 are non-empty, choose one of the following options:

  • If word1 is non-empty, append the first character in word1 to merge and delete it from word1.
    • For example, if word1 = "abc" and merge = "dv", then after choosing this operation, word1 = "bc" and merge = "dva".
  • If word2 is non-empty, append the first character in word2 to merge and delete it from word2.
    • For example, if word2 = "abc" and merge = "", then after choosing this operation, word2 = "bc" and merge = "a".

Return the lexicographically largest merge you can construct.

A string a is lexicographically larger than a string b (of the same length) if in the first position where a and b differ, a has a character strictly larger than the corresponding character in b. For example, "abcd" is lexicographically larger than "abcc" because the first position they differ is at the fourth character, and d is greater than c.

 

Example 1:

Input: word1 = "cabaa", word2 = "bcaaa"
Output: "cbcabaaaaa"
Explanation: One way to get the lexicographically largest merge is:
- Take from word1: merge = "c", word1 = "abaa", word2 = "bcaaa"
- Take from word2: merge = "cb", word1 = "abaa", word2 = "caaa"
- Take from word2: merge = "cbc", word1 = "abaa", word2 = "aaa"
- Take from word1: merge = "cbca", word1 = "baa", word2 = "aaa"
- Take from word1: merge = "cbcab", word1 = "aa", word2 = "aaa"
- Append the remaining 5 a's from word1 and word2 at the end of merge.

Example 2:

Input: word1 = "abcabc", word2 = "abdcaba"
Output: "abdcabcabcaba"

 

Constraints:

  • 1 <= word1.length, word2.length <= 3000
  • word1 and word2 consist only of lowercase English letters.

Solution

largest-merge-of-two-strings.py
class Solution:
    def largestMerge(self, word1: str, word2: str) -> str:
        res = ""

        while word1 and word2:
            if word1 >= word2:
                res += word1[0]
                word1 = word1[1:]
            else:
                res += word2[0]
                word2 = word2[1:]

        res += word1 or word2

        return res
largest-merge-of-two-strings.cpp
class Solution {
public:
    string largestMerge(string s, string t) {
        string ans;
        int i = 0, j = 0;
        while(i < s.size() && j < t.size()) {
            if(s.substr(i) >= t.substr(j)) {
                ans += s[i];
                ++i;
            } else {
                ans += t[j];
                ++j;
            }
        }
        while(i < s.size()) {
            ans += s[i];
            ++i;
        }
        while(j < t.size()) {
            ans += t[j];
            ++j;
        }
        return ans;
    }
};