题解 | #单词拆分(一)#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param s string字符串 
     * @param dic string字符串一维数组 
     * @return bool布尔型
     */
    public boolean wordDiv (String s, String[] dic) {
        // write code here
        if (s == null || s.length() < 1 || dic == null) {
            return false;
        }
        Set<String> set = new HashSet<>(Arrays.asList(dic));
        int n = s.length();
        boolean[] dp = new boolean[n + 1];
        dp[0] = true;
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < i; j++) {
                if (dp[j] && set.contains(s.substring(j, i))) {
                    dp[i] = true;
                    break;
                }
            }
        }
        return dp[n];
    }
}