Day40 动态规划 — 完全背包

139. 单词拆分

class Solution {
    // 背包 = 字符串s，物品 = 字符串列表
    // 完全背包，排列
public:
    bool wordBreak(string s, vector& wordDict) {
        unordered_set word_set(wordDict.begin(), wordDict.end());
        vector dp(s.size() + 1, false);
        dp[0] = true;
        
        for (int i = 1; i <= s.size(); i++) {
            for (int j = 0; j < i; j++) {
                string word = s.substr(j, i - j);
                if (word_set.find(word) != word_set.end() && dp[j]) {
                    dp[i] = true;
                }
            }
        }

        return dp[s.size()];
    }
};