524

524. Longest Word in Dictionary through Deleting (Medium)

Given a string s and a string array dictionary, return the longest string in the dictionary that can be formed by deleting some of the given string characters. If there is more than one possible result, return the longest word with the smallest lexicographical order. If there is no possible result, return the empty string.

 

Example 1:

Input: s = "abpcplea", dictionary = ["ale","apple","monkey","plea"]
Output: "apple"

Example 2:

Input: s = "abpcplea", dictionary = ["a","b","c"]
Output: "a"

 

Constraints:

• 1 <= s.length <= 1000
• 1 <= dictionary.length <= 1000
• 1 <= dictionary[i].length <= 1000
• s and dictionary[i] consist of lowercase English letters.

Companies:
Google

Related Topics:
Array, Two Pointers, String, Sorting

Similar Questions:

• Longest Word in Dictionary (Medium)

Solution 1. Two Pointers

// OJ: https://leetcode.com/problems/longest-word-in-dictionary-through-deleting/
// Author: github.com/lzl124631x
// Time: O(MNW)
// Space: O(1)
class Solution {
public:
    string findLongestWord(string s, vector<string>& A) {
        string ans;
        auto valid = [](string &a, string &b) {
            int i = 0, j = 0, M = a.size(), N = b.size();
            if (M > N) return false;
            for (; i < M; ++i, ++j) {
                while (j < N && b[j] != a[i]) ++j;
                if (j == N) return false;
            }
            return true;
        };
        for (auto &w : A) {
            if (w.size() >= ans.size() && valid(w, s) && (w.size() > ans.size() || w < ans)) ans = w; 
        }
        return ans;
    }
};