Commit 43b8ac1

committed

Climbing Stairs

1 parent bc097f1 commit 43b8ac1Copy full SHA for 43b8ac1

File tree

+33

-8

lines changed

+33

-8

lines changed

Lines changed: 33 additions & 8 deletions

Original file line number	Diff line number	Diff line change
`@@ -22,11 +22,36 @@`
`22`	`22`	`2. 1 step + 2 steps`
`23`	`23`	`3. 2 steps + 1 step`
`24`	`24`	`"""`
`25`		`-class Solution(object):`
`26`		`- def climbStairs(self, n):`
`27`		`- if n == 1:`
`28`		`- return 1`
`29`		`- a,b = 1,2`
`30`		`- for _ in range(2,n):`
`31`		`- a,b = b, a+b`
`32`		`- return b`
	`25`	`+class Solution:`
	`26`	`+ def climbStairs(self, n: int) -> int:`
	`27`	`+ if n <= 2:`
	`28`	`+ return n`
	`29`	`+`
	`30`	`+ second_last_stair, last_stair = 1, 2`
	`31`	`+`
	`32`	`+ for _ in range(3, n+1):`
	`33`	`+ second_last_stair, last_stair = last_stair, last_stair + second_last_stair`
	`34`	`+`
	`35`	`+ return last_stair`
	`36`	`+`
	`37`	`+`
	`38`	`+class Solution1:`
	`39`	`+ def climbStairs(self, n: int) -> int:`
	`40`	`+ return self.helper(n, {})`
	`41`	`+`
	`42`	`+ def helper(self, n, memo):`
	`43`	`+ if n <= 2:`
	`44`	`+ return n`
	`45`	`+`
	`46`	`+ if n not in memo:`
	`47`	`+ memo[n] = self.helper(n-1, memo) + self.helper(n-2, memo)`
	`48`	`+`
	`49`	`+ return memo[n]`
	`50`	`+`
	`51`	`+`
	`52`	`+# TLE`
	`53`	`+class Solution2:`
	`54`	`+ def climbStairs(self, n: int) -> int:`
	`55`	`+ if n <= 2:`
	`56`	`+ return n`
	`57`	`+ return self.climbStairs(n-1) + self.climbStairs(n-2)`

Comments

(0)