day-182.cpp

/*

 Word Break

Given a non-empty string s and a dictionary wordDict containing a list of
non-empty words, determine if s can be segmented into a space-separated sequence
of one or more dictionary words.

Note:

The same word in the dictionary may be reused multiple times in the
segmentation. You may assume the dictionary does not contain duplicate words.
Example 1:

Input: s = "leetcode", wordDict = ["leet", "code"]
Output: true
Explanation: Return true because "leetcode" can be segmented as "leet code".
Example 2:

Input: s = "applepenapple", wordDict = ["apple", "pen"]
Output: true
Explanation: Return true because "applepenapple" can be segmented as "apple pen
apple". Note that you are allowed to reuse a dictionary word. Example 3:

Input: s = "catsandog", wordDict = ["cats", "dog", "sand", "and", "cat"]
Output: false

*/

// Solved using hash map

class Solution {
   public:
    bool wordBreak(string s, vector<string>& wordDict) {
        int len = s.size();

        vector<bool> dp(len + 1, false);

        dp[0] = true;

        for (int i = 1; i <= len; i++) {
            for (int j = 0; j < i; j++) {
                if ((dp[j]) && (find(wordDict.begin(), wordDict.end(),
                                     s.substr(j, i - j)) != wordDict.end())) {
                    dp[i] = true;
                    break;
                }
            }
        }

        return dp.back();
    }
};