139. 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"

.

Subscribe to see which companies asked this question
从头开始一截一截找……

public class Solution {
private boolean search (String s,List<String> dic){
if(s.length()==0)return true;
for(int i = 0;i<dic.size();i++){
int sign = 0;
String tem = dic.get(i);
if(tem.length()>s.length())continue;
for(int j = 0;j<tem.length();j++){
if(tem.charAt(j)==s.charAt(j))continue;
sign = 1;break;
}
if(sign==1)continue;
String ss = s.substring(tem.length());
if(search(ss,dic)==true)return true;
}
return false;
}
public boolean wordBreak(String s, Set<String> wordDict) {
List<String> dic = new ArrayList(wordDict);//先把不可能的字段删了
for(int i = 0;i<dic.size();){
if(s.indexOf(dic.get(i))!=-1){i++;continue;}
dic.remove(i);
}
for(int i = dic.size()-1;i>=0;i--){//如果dict中有字符串能用其他字符串表示，就把该字符串删掉
String tem = dic.get(i);
dic.remove(i);
if(search(tem,dic)==true)continue;
dic.add(tem);
}
return search(s,dic);
}
}