May 30, 2023 · Apr 6, 2023 · May 5, 2023 · May 5, 2023 · May 8, 2023 · May 29, 2023
diff --git a/problems/0093.复原IP地址.md b/problems/0093.复原IP地址.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -316,6 +316,47 @@ class Solution {
		return true;
		}
		}
	//方法一:但使用stringBuilder,故优化时间、空间复杂度,因为向字符串插入字符时无需复制整个字符串,从而减少了操作的时间复杂度,也不用开新空间存subString,从而减少了空间复杂度。
	class Solution {
	List<String> result = new ArrayList<>();
	public List<String> restoreIpAddresses(String s) {
	StringBuilder sb = new StringBuilder(s);
	backTracking(sb, 0, 0);
	return result;
	}
	private void backTracking(StringBuilder s, int startIndex, int dotCount){
	if(dotCount == 3){
	if(isValid(s, startIndex, s.length() - 1)){
	result.add(s.toString());
	}
	return;
	}
	for(int i = startIndex; i < s.length(); i++){
	if(isValid(s, startIndex, i)){
	s.insert(i + 1, '.');
	backTracking(s, i + 2, dotCount + 1);
	s.deleteCharAt(i + 1);
	}else{
	break;
	}
	}
	}
	//[start, end]
	private boolean isValid(StringBuilder s, int start, int end){
	if(start > end)
	return false;
	if(s.charAt(start) == '0' && start != end)
	return false;
	int num = 0;
	for(int i = start; i <= end; i++){
	int digit = s.charAt(i) - '0';
	num = num * 10 + digit;
	if(num > 255)
	return false;
	}
	return true;
	}
	}

		//方法二:比上面的方法时间复杂度低,更好地剪枝,优化时间复杂度
		class Solution {
Expand Down Expand Up		@@ -360,6 +401,7 @@ class Solution {
		}
		```


		## python

		回溯(版本一)
Expand Down