• Question
• Solution

Question

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given

s = "leetcode",

dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

Solution

Result: Accepted Time: 16 ms

Here should be some explanations.

class Solution {
public:
    bool wordBreak(string s, unordered_set<string>& wordDict) {
        const int n = s.length();
        vector<bool> f(n + 1, false);
        f[0] = true;
        for (int i = 1; i <= n; i ++)
            for (int j = 0; j < i; j ++)
                if(f[i] =  f[j] && wordDict.count(s.substr(j, i - j)))
                    break;
        return f[n];
    }
};

Complexity Analytics

• Time Complexity: $O(n^2)$
• Space Complexity: $O(n)$