[Gold III] Title: 크게 만들기, Time: 92 ms, Memory: 80780 KB -BaekjoonHub

Author: 051198Hz

백준/Gold/2812. 크게 만들기/README.md

@@ -4,15 +4,15 @@
 
 ### 성능 요약
 
-메모리: 91524 KB, 시간: 628 ms
+메모리: 80780 KB, 시간: 92 ms
 
 ### 분류
 
 자료 구조, 그리디 알고리즘, 스택
 
 ### 제출 일자
 
-2024년 4월 15일 14:31:16
+2025년 8월 15일 00:58:48
 
 ### 문제 설명
 

백준/Gold/2812. 크게 만들기/크게 만들기.swift

@@ -1,115 +1,27 @@
-import Foundation
+let nk = readLine()!.split { $0 == " " }.map { Int($0)! },
+    n = nk[0],
+    k = nk[1]
+var numbers: [Int] = readLine()!.map { Int(String($0))! }.reversed()
 
-// MARK: - using FileIO, thanks to Wapas
+var stack = [Int]()
+var popCount = 0
 
-//print(answer.map{ "\($0)" }.joined(separator: " "))
-//collectoin을 전체출력할 땐 forEach 말고 [String]으로 변환 후 joined로 String으로 압축 후 print로 출력하는게 더 빠름
-
-var file = FileIO()
-
-let n = file.readInt()
-let k = file.readInt()
-let numbers = file.readString().map{ $0.wholeNumberValue! }
-let capacity = n - k
-var stack:[Int] = []
-
-for i in stride(from: n-1, to: -1, by: -1){
-    if stack.count < capacity{
-        stack.append(numbers[i])
-    }else if numbers[i] >= stack.last!{
-        for j in stride(from: capacity - 2, to: -1, by: -1){
-            if stack[j] > stack[j+1]{
-                stack.remove(at: j+1)
-                stack.append(numbers[i])
-                break
-            }
-            if j == 0 {
-                stack.remove(at: j)
-                stack.append(numbers[i])
-            }
-        }
+while popCount < k, !numbers.isEmpty {
+    guard let number = numbers.popLast() else { break }
+    while popCount < k, let last = stack.last, last < number {
+        stack.popLast()
+        popCount += 1
     }
+    stack.append(number)
 }
 
-print(stack.reversed().map{ "\($0)" }.joined())
-
-
-// MARK: - FileIO
-
-struct FileIO {
-    private let buffer:[UInt8]
-    private var index: Int = 0
-
-    init(fileHandle: FileHandle = FileHandle.standardInput) {
-
-        buffer = Array(try! fileHandle.readToEnd()!)+[UInt8(0)] // 인덱스 범위 넘어가는 것 방지
-    }
-
-    @inline(__always) private mutating func read() -> UInt8 {
-        defer { index += 1 }
-
-        return buffer[index]
-    }
-
-    @inline(__always) mutating func readInt() -> Int {
-        var sum = 0
-        var now = read()
-        var isPositive = true
-
-        while now == 10
-                || now == 32 { now = read() } // 공백과 줄바꿈 무시
-        if now == 45 { isPositive.toggle(); now = read() } // 음수 처리
-        while now >= 48, now <= 57 {
-            sum = sum * 10 + Int(now-48)
-            now = read()
-        }
-
-        return sum * (isPositive ? 1:-1)
-    }
-
-    mutating func readIntArray(_ K: Int) -> [Int] {
-        var array = [Int]()
-
-        for _ in 0..<K {
-            array.append(readInt())
-        }
-
-        return array
-    }
-
-    @inline(__always) mutating func readString() -> String {
-        var now = read()
-
-        while now == 10 || now == 32 { now = read() } // 공백과 줄바꿈 무시
-        let beginIndex = index-1
-
-        while now != 10,
-              now != 32,
-              now != 0 { now = read() }
-
-        return String(bytes: Array(buffer[beginIndex..<(index-1)]), encoding: .ascii)!
-    }
-
-    mutating func readStringArray(_ K: Int) -> [String] {
-        var array = [String]()
-
-        for _ in 0..<K {
-            array.append(readString())
-        }
-
-        return array
-    }
-
-    @inline(__always) mutating func readByteSequenceWithoutSpaceAndLineFeed() -> [UInt8] {
-        var now = read()
-
-        while now == 10 || now == 32 { now = read() } // 공백과 줄바꿈 무시
-        let beginIndex = index-1
-
-        while now != 10,
-              now != 32,
-              now != 0 { now = read() }
+while !numbers.isEmpty {
+    stack.append(numbers.popLast()!)
+}
 
-        return Array(buffer[beginIndex..<(index-1)])
-    }
+while popCount < k {
+    stack.popLast()
+    popCount += 1
 }
+
+print(stack.map { "\($0)"}.joined())