[Swift] 백준 15552번 문제 빠른 A+B

https://www.acmicpc.net/problem/15552

15552번: 빠른 A+B

 

https://github.com/Ljunhyeob/baekjoon15552

GitHub - Ljunhyeob/baekjoon15552: 백준 - 15552

import Foundation

// 라이노님의 FileIO
final class FileIO {
    private var buffer:[UInt8]
    private var index: Int
    
    init(fileHandle: FileHandle = FileHandle.standardInput) {
        buffer = Array(fileHandle.readDataToEndOfFile())+[UInt8(0)] // 인덱스 범위 넘어가는 것 방지
        index = 0
    }
    
    @inline(__always) private func read() -> UInt8 {
        defer { index += 1 }
        
        return buffer.withUnsafeBufferPointer { $0[index] }
    }
    
    @inline(__always) 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)
    }
    
    @inline(__always) func readString() -> String {
        var str = ""
        var now = read()
        
        while now == 10
                || now == 32 { now = read() } // 공백과 줄바꿈 무시
        
        while now != 10
                && now != 32 && now != 0 {
            str += String(bytes: [now], encoding: .ascii)!
            now = read()
        }
        
        return str
    }
}

// 풀이
var answer = ""
func solution() {
    let a = file.readInt(), b = file.readInt()
    answer += "\(a + b)\n"
}

let file = FileIO()

let n = file.readInt()
for _ in 0..<n {
    solution()
}

print(answer)