May 29, 2023 · May 25, 2023 · May 26, 2023 · May 26, 2023 · May 26, 2023 · May 26, 2023
diff --git a/problems/0077.组合.md b/problems/0077.组合.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -377,68 +377,42 @@ class Solution {
		```

		### Python

	```python
	class Solution(object):
	def combine(self, n, k):
	"""
	:type n: int
	:type k: int
	:rtype: List[List[int]]
	"""
	result = []
	path = []
	def backtracking(n, k, startidx):
	if len(path) == k:
	result.append(path[:])
	return

	# 剪枝, 最后k - len(path)个节点直接构造结果,无需递归
	last_startidx = n - (k - len(path)) + 1

	for x in range(startidx, last_startidx + 1):
	path.append(x)
	backtracking(n, k, x + 1) # 递归
	path.pop() # 回溯

	backtracking(n, k, 1)
	return result
	```

	未剪枝优化
		```python
		class Solution:
		def combine(self, n: int, k: int) -> List[List[int]]:
	res = []
	path = []
	def backtrack(n, k, StartIndex):
	if len(path) == k:
	res.append(path[:])
	return
	for i in range(StartIndex, n + 1):
	path.append(i)
	backtrack(n, k, i+1)
	path.pop()
	backtrack(n, k, 1)
	return res
	result = [] # 存放结果集
	self.backtracking(n, k, 1, [], result)
	return result
	def backtracking(self, n, k, startIndex, path, result):
	if len(path) == k:
	result.append(path[:])
	return
	for i in range(startIndex, n + 1): # 需要优化的地方
	path.append(i) # 处理节点
	self.backtracking(n, k, i + 1, path, result)
	path.pop() # 回溯,撤销处理的节点

		```

	剪枝:

	剪枝优化:

		```python
		class Solution:
		def combine(self, n: int, k: int) -> List[List[int]]:
	res=[] #存放符合条件结果的集合
	path=[] #用来存放符合条件结果
	def backtrack(n,k,startIndex):
	if len(path) == k:
	res.append(path[:])
	return
	for i in range(startIndex,n-(k-len(path))+2): #优化的地方
	path.append(i) #处理节点
	backtrack(n,k,i+1) #递归
	path.pop() #回溯,撤销处理的节点
	backtrack(n,k,1)
	return res
	result = [] # 存放结果集
	self.backtracking(n, k, 1, [], result)
	return result
	def backtracking(self, n, k, startIndex, path, result):
	if len(path) == k:
	result.append(path[:])
	return
	for i in range(startIndex, n - (k - len(path)) + 2): # 优化的地方
	path.append(i) # 处理节点
	self.backtracking(n, k, i + 1, path, result)
	path.pop() # 回溯,撤销处理的节点

		```

		### Go
Expand Down