Commit ae9740d

committed

Combination Sum

1 parent 605bad8 commit ae9740dCopy full SHA for ae9740d

File tree

+40

-0

lines changed

+40

-0

lines changed

Lines changed: 39 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,39 @@`
	`1`	`+''' Leetcode- https://leetcode.com/problems/combination-sum/'''`
	`2`	`+'''`
	`3`	`+Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order.`
	`4`	`+`
	`5`	`+The same number may be chosen from candidates an unlimited number of times. Two combinations are unique if the frequency of at least one of the chosen numbers is different.`
	`6`	`+`
	`7`	`+It is guaranteed that the number of unique combinations that sum up to target is less than 150 combinations for the given input.`
	`8`	`+`
	`9`	`+Example 1:`
	`10`	`+`
	`11`	`+Input: candidates = [2,3,6,7], target = 7`
	`12`	`+Output: [[2,2,3],[7]]`
	`13`	`+Explanation:`
	`14`	`+2 and 3 are candidates, and 2 + 2 + 3 = 7. Note that 2 can be used multiple times.`
	`15`	`+7 is a candidate, and 7 = 7.`
	`16`	`+These are the only two combinations.`
	`17`	`+'''`
	`18`	`+`
	`19`	`+`
	`20`	`+def combinationSum(candidates, target):`
	`21`	`+ res = []`
	`22`	`+`
	`23`	`+ def dfs(i, cur, total):`
	`24`	`+ if total == target:`
	`25`	`+ res.append(cur.copy())`
	`26`	`+ return`
	`27`	`+ if i >= len(candidates) or total > target:`
	`28`	`+ return`
	`29`	`+`
	`30`	`+ cur.append(candidates[i])`
	`31`	`+ dfs(i, cur, total+candidates[i])`
	`32`	`+ cur.pop()`
	`33`	`+ dfs(i+1, cur, total)`
	`34`	`+`
	`35`	`+ dfs(0, [], 0)`
	`36`	`+ return res`
	`37`	`+`
	`38`	`+#T: O(2^T)`
	`39`	`+#S: O(N)`

Lines changed: 1 addition & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -13,4 +13,5 @@ Check the notes for the explaination - [Notes](https://stingy-shallot-4ea.notion`
`13`	`13`	`- [x] [Permutations](Backtracking/46-Permutations.py)`
`14`	`14`	`- [x] [Permutations II](Backtracking/47-Permutations-II.py)`
`15`	`15`	`- [x] [Combinations](Backtracking/77-Combinations.py)`
	`16`	`+ - [x] [Combination Sum](Backtracking/39-Combination-Sum.py)`
`16`	`17`

Comments

(0)