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".

public class Solution {
    public boolean wordBreak(String s, Set<String> dict) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(s == null || s.length() == 0) return true;
        int len = s.length();
        boolean[] map = new boolean[len];
        for(int i = len - 1; i > -1; i --){
            for(int j = i + 1; j <= len; j ++){
                String ss = s.substring(i,j);
                if(dict.contains(ss) && j == len){
                    map[i] = true;
                    break;
                }
                else if(dict.contains(ss) && j < len && map[j] == true){
                    map[i] = true;
                    break;
                }
            }
        }
        return map[0];
    }
}

 第二遍：

public class Solution {
    public boolean wordBreak(String s, Set<String> dict) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(s == null || s.length() == 0) return true;
        int len = s.length();
        boolean[] map = new boolean[len];
        for(int i = len - 1; i > -1; i --)
            for(int j = i + 1; j <= len; j ++){
                    if(j < len && !map[j]) continue;
                    else if(dict.contains(s.substring(i, j)) && (j == len || map[j])){
                        map[i] = true;
                        break;
                    }
        }
        return map[0];
    }
}