解法

boolean类型的状态转移方程，一维就可以，没有必要使用二维

代码

import java.util.*;
import java.util.List;
class Solution {
    public boolean wordBreak(String s, List<String> wordDict) {
        /*boolean[] dp=new boolean[s.length()+1];
        dp[0]=true;
        for(int i=1;i<dp.length;i++)
        {
            for(int j=0;j<=i;j++)
            {
                if(wordDict.contains(s.substring(j,i))&&dp[j])
                {
                    dp[i]=true;
                    break;
                }
            }
        }
        return dp[dp.length-1];*/
        Set<String> wordDictSet=new HashSet(wordDict);
        boolean[] dp = new boolean[s.length() + 1];
        dp[0] = true;
        for (int i = 1; i <= s.length(); i++) {
            for (int j = 0; j < i; j++) {
                if (dp[j] && wordDictSet.contains(s.substring(j, i))) {
                    dp[i] = true;
                    break;
                }
            }
        }
        return dp[s.length()];
    }
}