[LeetCode]Repeated Substring Pattern(Java)，leetcoderepeated

[LeetCode]Repeated Substring Pattern(Java)，leetcoderepeated

这道题我的方法太暴力，人家解得巧妙不已，我的方法如下：

public class Solution {
    public boolean repeatedSubstringPattern(String str) {
        int length = str.length() / 2 +1;
        for(int i = 1;i<length;i++){
            String sub = str.substring(0,i);
            if(check(str.substring(i),sub))
                return true;
        }
        return false;
    }
    private boolean check(String str,String sub){
        int strLen = str.length(),subLen = sub.length();
        int checkNum = strLen % subLen;
        if(checkNum != 0){
            return false;
        }
        int i = 0;
        while(i <= strLen - subLen){
            
            String checkStr = str.substring(i,i+subLen);
            if(checkStr.equals(sub))
                i +=subLen;
            else
                return false;
        }
        return true;
        
    }
}

讨论中高票答案：

public boolean repeatedSubstringPattern(String str) {
	int l = str.length();
	for(int i=l/2;i>=1;i--) {
		if(l%i==0) {
			int m = l/i;
			String subS = str.substring(0,i);
			StringBuilder sb = new StringBuilder();
			for(int j=0;j<m;j++) {
				sb.append(subS);
			}
			if(sb.toString().equals(str)) return true;
		}
	}
	return false;
}

2016/12/15