-
Notifications
You must be signed in to change notification settings - Fork 53
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #484 from haklee/main
[haklee] week 7
- Loading branch information
Showing
5 changed files
with
189 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,51 @@ | ||
"""TC: O(n), SC: O(n) | ||
์์ด๋์ด: | ||
ํฌํฌ์ธํฐ๋ก ๋ฌธ์์ด์ ์์, ๋ ์ธ๋ฑ์ค๋ฅผ ๊ด๋ฆฌํ๋ค. ๊ทธ๋ฆฌ๊ณ ๋ฌธ์์ด ์์ ์๋ ๋ฌธ์๋ฅผ set์ผ๋ก ๊ด๋ฆฌํ๋ค. | ||
- ์์~๋ ์ฌ์ด์ ๋ชจ๋ ๋ฌธ์๊ฐ ์๋ก ๋ค๋ฅด๋ฉด ๋ ์ธ๋ฑ์ค๋ฅผ ํ๋ ๋ค๋ก ์ฎ๊ธด๋ค. | ||
- ์๋ก์ด ๋ฌธ์์ด์ ์ ์ผ ๋์ ์๋ ๋ฌธ์๊ฐ ํน์ set ์์ ์์ผ๋ฉด ์์ ์ธ๋ฑ์ค๋ฅผ ๋ค๋ก ์ฎ๊ธฐ๋ ์์ ์ | ||
ํด๋น ๋ฌธ์๋ ๊ฐ์ ๋ฌธ์๊ฐ ๋์ฌ ๋๊น์ง ์งํํ๋ค. ์ฆ, ๋์ ๊ณ ์ ํ๊ณ ์์ ๊ณ์ ์ฎ๊ฒจ์ ์๋ก์ด ๋ฌธ์์ด์ | ||
์๋ ๋ชจ๋ ๋ฌธ์๋ค์ด ๋ค๋ฅธ ๋ฌธ์๊ฐ ๋๋๋ก ๋ง๋ ๋ค. | ||
- e.g.) abcdefd -> abcdefd | ||
^ ^ ^ ^ | ||
s e s e | ||
- ์์ ๊ณผ์ ์ ๊ณ์ ๋ฐ๋ณตํ๋ฉด์ ๋ฌธ์์ด์ ์ต๋ ๊ธธ์ด ๊ฐ์ ๊ฐฑ์ ํ๋ค. | ||
SC: | ||
- ์๋ก์ด ๋ฌธ์์ด์ ์์๊ณผ ๋ ์ธ๋ฑ์ค ๊ฐ์ ๊ด๋ฆฌํ๋ ๋ฐ์ O(1). | ||
- ์๋ก์ด ๋ฌธ์์ด ์์ ๋ค์ด์๋ ๋ฌธ์๋ฅผ set์ผ๋ก ๊ด๋ฆฌํ๋ ๋ฐ์ ์ต์ ์ ๊ฒฝ์ฐ n๊ฐ์ ๋ฌธ์๊ฐ ๋ชจ๋ ๋ค๋ฅผ๋ O(n). | ||
- ์ต๋ ๋ฌธ์์ด ๊ธธ์ด๋ฅผ ๊ด๋ฆฌํ๋ ๋ฐ์ O(1). | ||
- ์ข ํฉํ๋ฉด O(n). | ||
TC: | ||
- s, e๋ ๋ชจ๋ ๋ฌธ์์ด์ ์ธ๋ฑ์ค๋ฅผ ๋ํ๋ด๋ฏ๋ก s, e๊ฐ์ ์๋ฌด๋ฆฌ ๋ง์ด ์ ๋ฐ์ดํธ ํด๋ ๊ฐ๊ฐ ๋ฌธ์์ด ๊ธธ์ด๋ณด๋ค | ||
๋ง์ด ์ ๋ฐ์ดํธ ํ ์๋ ์๋ค. ์ฆ, O(n). | ||
- set์์ ํน์ ๋ฌธ์๊ฐ ๋ค์ด์๋์ง ์ฒดํฌํ๊ณ set์ ๋ฌธ์๋ฅผ ๋ํ๊ฑฐ๋ ์ ๊ฑฐํ๋ ๋ฐ์ O(1). ์ด ์์ ์ ์๋ฌด๋ฆฌ | ||
๋ง์ด ํด๋ s, e๋ฅผ ์ ๋ฐ์ดํธ ํ๋ ํ์ ๋งํผ ์งํํ๋ฏ๋ก ์ด O(n). | ||
- ์ต๋ ๋ฌธ์์ด ๊ธธ์ด๋ฅผ ์ ๋ฐ์ดํธ ํ๋ ๋ฐ์ O(1). ์ด ๋ํ ์๋ฌด๋ฆฌ ๋ง์ด ์งํํด๋ O(n). | ||
- ์ข ํฉํ๋ฉด O(n). | ||
""" | ||
|
||
|
||
class Solution: | ||
def lengthOfLongestSubstring(self, string: str) -> int: | ||
if len(string) < 1: | ||
return 0 | ||
s = e = 0 | ||
letter_set = set([string[0]]) | ||
sol = 1 | ||
while True: | ||
e += 1 | ||
if e == len(string): | ||
break | ||
|
||
if string[e] in letter_set: | ||
while True: | ||
letter_set.discard(string[s]) | ||
if string[s] == string[e]: | ||
break | ||
s += 1 | ||
s += 1 | ||
letter_set.add(string[e]) | ||
sol = max(len(letter_set), sol) | ||
return sol |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,41 @@ | ||
"""TC: O(m * n), SC: O(m * n) | ||
์์ด๋์ด: | ||
- ํน์ ์นธ์ด 1์ผ ๊ฒฝ์ฐ ์ด์ ๊ฐ์ ์ฌ ์์ ์๋ ๋ชจ๋ ์นธ๋ค์ 0์ผ๋ก ๋ฐ๊ฟ์ฃผ๋ `remove_ground` ํจ์ ๊ตฌํ. | ||
- grid ๋ด์ ๋ชจ๋ ์นธ๋ค์ ๋๋ฉด์ `remove_ground`๊ฐ ๋ช ๋ฒ ์ต์ด ํธ์ถ(์ฆ, ์ฌ๊ท ํธ์ถ ์๋) ๋์๋์ง | ||
์ธ๋ฉด ์ ์ฒด ์ฌ์ด ๋ช ๊ฐ ์๋์ง ์ฐพ์ ์ ์๋ค. | ||
SC: | ||
- ๋ชจ๋ ์นธ์ด ์ ๋ถ 1์ผ ๊ฒฝ์ฐ remove_ground์ ํธ์ถ ์คํ ๊น์ด๊ฐ m*n์ด ๋๋ค. ์ฆ, O(m * n). | ||
TC: | ||
- ๊ฐ ๋ ธ๋๋ ์ต๋ 5๋ฒ์ฉ ์ ๊ทผ๋ ์ ์๋ค. | ||
- ์ด์ํ ์นธ์์ remove_ground ํ๋ฉด์ ์ ๊ทผ | ||
- ์ต์ธ๊ณฝ์์ ํด๋น ์นธ์ด 1์ธ์ง ์ฒดํฌํ๋ฉด์ ์ ๊ทผ | ||
- ์ ๊ทผํ๊ณ ๋์ ํ๋ ์ฐ์ฐ์ด O(1). | ||
- ํด๋น ์นธ์ ๊ฐ์ด 1์ธ์ง ์ฒดํฌํ๋ ๋ฐ์ O(1). | ||
- check_inside ์ฐ์ฐ์ 4๋ฒ ํ ์ ์๋๋ฐ ๊ฐ๊ฐ O(1). | ||
- ์ข ํฉํ๋ฉด O(1). | ||
- ์ข ํฉํ๋ฉด O(m * n). | ||
""" | ||
|
||
|
||
class Solution: | ||
def numIslands(self, grid: List[List[str]]) -> int: | ||
minx, miny, maxx, maxy = 0, 0, len(grid[0]) - 1, len(grid) - 1 | ||
|
||
def remove_ground(i, j): | ||
if minx <= j <= maxx and miny <= i <= maxy and grid[i][j] == "1": | ||
grid[i][j] = "0" | ||
remove_ground(i - 1, j) | ||
remove_ground(i + 1, j) | ||
remove_ground(i, j - 1) | ||
remove_ground(i, j + 1) | ||
|
||
sol = 0 | ||
for i in range(maxy + 1): | ||
for j in range(maxx + 1): | ||
if grid[i][j] == "1": | ||
sol += 1 | ||
remove_ground(i, j) | ||
return sol |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,28 @@ | ||
"""TC: O(n), SC: O(1) | ||
์์ด๋์ด: | ||
์ฒซ ์์ดํ ๋ถํฐ ์ฐจ๋ก๋๋ก next๋ก ๋์ด๊ฐ๋ฉด์ ์ง์ ์ ๋ณด์๋ ๋ ธ๋๋ฅผ next์ ๋ฃ์ด์ค๋ค. | ||
SC: | ||
- ์ง์ ๋ ธ๋๋ฅผ ๊ด๋ฆฌํ๋ค. O(1). | ||
TC: | ||
- ๋ชจ๋ ๋ ธ๋์ ๋ํด ์ง์ ๋ ธ๋๋ฅผ next์ ๋์ ํ๋ค. | ||
- ๊ทธ ์ธ์ ๋ค๋ฅธ ์ฐ์ฐ๋ O(1). ์ฝ๋ ์ฐธ์กฐ. | ||
- ์ข ํฉํ๋ฉด O(n). | ||
""" | ||
|
||
|
||
# Definition for singly-linked list. | ||
# class ListNode: | ||
# def __init__(self, val=0, next=None): | ||
# self.val = val | ||
# self.next = next | ||
class Solution: | ||
def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]: | ||
prev, cur = None, head | ||
while cur: | ||
next = cur.next | ||
cur.next = prev | ||
prev, cur = cur, next | ||
return prev |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,38 @@ | ||
"""TC: O(m * n), SC: O(m + n) | ||
์์ด๋์ด: | ||
๋ชจ๋ ์นธ์ ํ์ผ๋ฉด์ ์ด๋ค row, column์ 0์ผ๋ก ๋ฐ๊ฟ์ค์ผ ํ๋์ง ์ฐพ์ ๋ค์ 0์ผ๋ก ๋ฐ๊พธ๋ ์ํ์ ํ๋ค. | ||
SC: | ||
- ๋ฐ๊ฟ์ผ ํ๋ column, row๋ฅผ set์ผ๋ก ๊ด๋ฆฌ. ๊ฐ๊ฐ O(m), O(n)์ด๋ฏ๋ก ์ข ํฉํ๋ฉด O(m + n). | ||
TC: | ||
- ๋ชจ๋ ์นธ์ ๋๋ฉด์ ์ด๋ค column๊ณผ row๋ฅผ 0์ผ๋ก ๋ฐ๊ฟ์ผ ํ๋์ง ์ฒดํฌํ๋ค. O(m * n). | ||
- 0์ผ๋ก ๋ฐ๊ฟ์ผ ํ๋ ๋ชจ๋ column์ 0์ผ๋ก ๋ฐ๊พผ๋ค. ๋ชจ๋ column์ ๋ค 0์ผ๋ก ๋ฐ๊ฟ์ผ ํ ๊ฒฝ์ฐ ๋ชจ๋ ์นธ์ | ||
์ ๊ทผํด์ 0์ ๋ฃ์ด์ฃผ์ด์ผ ํ๋ฏ๋ก O(m * n). | ||
- row๋ column๊ณผ ๋๊ฐ์ด ์ ๊ทผ ๊ฐ๋ฅํ๋ค. O(m * n). | ||
- ์ข ํฉํ๋ฉด O(m * n). | ||
""" | ||
|
||
|
||
class Solution: | ||
def setZeroes(self, matrix: List[List[int]]) -> None: | ||
""" | ||
Do not return anything, modify matrix in-place instead. | ||
""" | ||
m, n = len(matrix), len(matrix[0]) | ||
col_to_change, row_to_change = set(), set() | ||
|
||
for i in range(m): | ||
for j in range(n): | ||
if matrix[i][j] == 0: | ||
col_to_change.add(i) | ||
row_to_change.add(j) | ||
|
||
for i in col_to_change: | ||
for j in range(n): | ||
matrix[i][j] = 0 | ||
|
||
for j in row_to_change: | ||
for i in range(m): | ||
matrix[i][j] = 0 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,31 @@ | ||
"""TC: O(m + n), SC: O(1) | ||
์์ด๋์ด: | ||
์ค๋ฅธ์ชฝ์ผ๋ก ๊ฐ๋ ํ์ m-1, ์๋๋ก ๊ฐ๋ ํ์ n-1์ ์์ ์ ์๋ ๋ฐฉ๋ฒ์ ์๋ฅผ ๊ตฌํ๋ฉด ๋๋ค. | ||
์ฆ, m+n-2ํ์ ์ด๋ ์ค m-1๊ฐ๋ฅผ ๋ฝ์์ ์ค๋ฅธ์ชฝ์ผ๋ก ๊ฐ๊ณ , ๋๋จธ์ง๋ฅผ ์๋๋ก ๊ฐ๋ฉด ๋๋ค. | ||
์ฆ, (m+n-2)C(m-1)์ ๊ณ์ฐํ๋ฉด ๋๋ค. | ||
ํฐ ์ ์ฐ์ฐ์ด ๊ฐ๋ฅํ ์ธ์ด๋ฅผ ์ฌ์ฉํ๋ฉด nCk = n! / (k! * (n - k)!) ๊ฐ์ ๊ณ์ฐํ๋ฉด ๋๋ค. | ||
ํ์ด์ฌ์ math.comb ํจ์๋ ์๋์ ๊ฐ์ด ์๋ํ๋ค. | ||
(ref: https://docs.python.org/ko/3/library/math.html#math.comb) | ||
- math.comb(n, k)์ ๊ณ์ฐํ๋ฉด k <= n์ด๋ฉด n! / (k! * (n - k)!)๋ก ํ๊ฐ๋๊ณ , k > n์ด๋ฉด 0์ผ๋ก ํ๊ฐ๋ฉ๋๋ค. | ||
์ด ํจ์๋ฅผ ์จ์ ๋์จ ๊ฒฐ๊ณผ๊ฐ์ ๊ทธ๋๋ก ๋ฐํํ์. | ||
SC: | ||
- ๊ณฑ์ , ๋๋์ ์ฐ์ฐ ๊ฒฐ๊ณผ ๊ฐ ๊ด๋ฆฌ. O(1). | ||
- ์์ฃผ ํฐ ์ซ์๋ฅผ ๋ค๋ฃฐ ๊ฒฝ์ฐ ์ด๋ ๊ฒ ๋ณด๋ฉด ์ ๋ ์๋ ์์ง๋ง, ๋ฌธ์ ์กฐ๊ฑด์ ๋ณด์ํ๋ int64 ๋ฒ์ ๋ด์์ | ||
๊ณฑ์ ๊ณผ ๋๋์ ์ฐ์ฐ ๊ฐ๋ค์ด ๋ชจ๋ ์ฒ๋ฆฌ๋๋ ๊ฒ์ผ๋ก ๋ณด์ธ๋ค. ์ฆ, SC๊ฐ ๊ทธ๋ฆฌ ์ค์ํ์ง๋ ์๋ค. | ||
TC: | ||
- (m+n-2)C(m-1) = (m+n-2)! / (m-1)! * (n-1)! | ||
- ๊ฐ ๊ณฑ์ ๊ฐ์ ๊ตฌํ๋ ๋ฐ์ O(m + n), O(m), O(n). ์ ๋ค ๋ํ๋ฉด O(m + n). | ||
- ๋๋์ ์ O(1). | ||
- ์ข ํฉํ๋ฉด O(m + n) | ||
""" | ||
|
||
from math import comb | ||
|
||
|
||
class Solution: | ||
def uniquePaths(self, m: int, n: int) -> int: | ||
return comb(m + n - 2, n - 1) |