swift warmup 10/4

valid-sudoku

Transcript

1. Swift ఔࣜখ೤਎ Valid Sudoku John Lin
2. Valid Sudoku • https://leetcode.com/problems/valid-sudoku/
3. • Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules. • ࠜᎦᏐᘐنଇိ൑ᏗҰݸᏐᘐੋෆੋ༗Ꮘతɻ
5. • http://www.websudoku.com/
6. • The Sudoku board could be partially filled, where empty cells are filled with the character '.'. • Ꮠᘐత൫໘༗Մೳੋෆ׬੔తɼۭനత஍ํ။ੋ .(ᴍ ᥒ)
7. ୊໨ࠎՍ class Solution { func isValidSudoku(_ board: [[Character]]) -> Bool { } } let board = [
 “.87654321",
 "2........",
 "3........",
 "4........",
 "5........",
 "6........",
 "7........",
 "8........",
 "9........"]
8. ᒾҰҰℷഉཫ༗ᔒ༗ॏෳ for row in board { var set = Set<Character>() for char in row { guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } }
9. ᒾҰҰ௚ߦཫ༗ᔒ༗ॏෳ for col in 0..<9 { var set = Set<Character>() for row in 0..<9 { let char = board[row][col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } }
10. ᒾҰეմத༗ᔒ༗ॏෳ for blockRow in 0..<3 { for blockCol in 0..<3 { var set = Set<Character>() for row in 0..<3 { for col in 0..<3 { let char = board[blockRow*3 + row] [blockCol*3 + col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } } }
11. શ෦౎ՄҎ return true
12. class Solution { func isValidSudoku(_ board: [[Character]]) -> Bool { for row in board { var set = Set<Character>() for char in row { guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } for col in 0..<9 { var set = Set<Character>() for row in 0..<9 { let char = board[row][col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } for blockRow in 0..<3 { for blockCol in 0..<3 { var set = Set<Character>() for row in 0..<3 { for col in 0..<3 { let char = board[blockRow*3 + row][blockCol*3 + col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } } } return true } } Runtime: 119 ms (50%)
13. class Solution { func isValidSudoku(_ board: [[Character]]) -> Bool { for row in board { var set = Set<Character>() for char in row { guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } for col in 0..<9 { var set = Set<Character>() for row in 0..<9 { let char = board[row][col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } for blockRow in 0..<3 { for blockCol in 0..<3 { var set = Set<Character>() for row in 0..<3 { for col in 0..<3 { let char = board[blockRow*3 + row][blockCol*3 + col] guard char != "." else { continue } guard !set.contains(char) else { return false } set.insert(char) } } } } return true } }
14. ೺௨༻త෦෼፮ग़ိ class Checker { var set = Set<Character>() func check(_ c:Character) -> Bool { guard c != "." else { return true } guard !set.contains(c) else { return false } set.insert(c) return true } }
15. class Solution { func isValidSudoku(_ board: [[Character]]) -> Bool { for row in board { let checker = Checker() for char in row { guard checker.check(char) else { return false } } } for col in 0..<9 { let checker = Checker() for row in 0..<9 { let char = board[row][col] guard checker.check(char) else { return false } } } for blockRow in 0..<3 { for blockCol in 0..<3 { let checker = Checker() for row in 0..<3 { for col in 0..<3 { let char = board[blockRow*3 + row][blockCol*3 + col] guard checker.check(char) else { return false } } } } } return true } } Runtime: 135 ms(40%)
16. Ճշ Checker class Checker { var set = Array(repeating: false, count: 9) let base = Int("1".unicodeScalars.first!.value) func check(_ c:Character) -> Bool { guard c != "." else { return true } let idx:Int = Int(String(c).unicodeScalars.first!.value) - base guard set[idx] != true else { return false } set[idx] = true return true } } Runtime: 95 ms(80%)
17. Q&A