139. Word Break （DP）

打印字符串的一个字符用str.charAt()
substring用str.subString()

要用这个字母之前几个能否组成word这样来考虑

 

https://leetcode.com/problems/word-break/discuss/43790/Java-implementation-using-DP-in-two-ways

 

 

class Solution {
    public boolean wordBreak(String s, List<String> wordDict) {
        int n = s.length();
        boolean[] res = new boolean[n + 1];
        res[0] = true;
        for(int i = 1; i < n + 1; i++) {
            for(int j = i - 1; j >= 0; j--) {
                if(res[j] && wordDict.contains(s.substring(j, i))) {
                    res[i] = true;
                    break;
                }
                res[i] = false; //boolean数组默认false
            }  
        }
        return res[n];
  }
}