Word Break

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".

Analyse: Use dynamic programming to solve this problem. 

class Solution {
public:
    bool wordBreak(string s, unordered_set<string>& wordDict) {
        vector<bool> canDivide(s.size() + 1, false);
        canDivide[0] = true;
        
        for (int i = 0; i < s.size(); i++) {
            for (int j = i; j >= 0; j--) {
                if (canDivide[i - j] && wordDict.find(s.substr(i - j, j + 1)) != wordDict.end()) {
                    canDivide[i + 1] = true;
                    break;
                }
            }
        }
        return canDivide[s.size()];
    }
};