1. 11279번 - 절대힙

//11279
import Foundation

var heap:[Int] = [0]

func add(a: Int) {
    var index = heap.count
    heap.append(a)
    while index > 1 && a > heap[index/2]{
        let temp = heap[index/2]
        heap[index/2] = a
        heap[index] = temp
        index /= 2
    }
}

func pop() -> Int {

    if heap.count <= 1 {
        return 0
    }
    
    let max = heap[1]
    let index = heap.count - 1
    heap[1] = heap[index]
    heap.remove(at: index)
    
    var parent = 1
    
    while parent <= (heap.count - 1) / 2 {
        var child = parent * 2
        if(child < heap.count - 1 && heap[child] < heap[child + 1]){
            child += 1
        }
        if (heap[parent] >= heap[child]) { break }
        
        let temp = heap[parent]
        heap[parent] = heap[child]
        heap[child] = temp
        parent = child
    }
    
    return max
}

let count = Int(readLine()!)!

for _ in 1...count {
    
    let input = Int(readLine()!)!
    if input == 0 {
        print(pop())
    } else if input > 0 {
        add(a: input)
    }
    
}

2. 11286 - 절대값 힙

//11286
import Foundation

var heap:[Int] = [0]

// 절대값이 작은 수가 부모가 됨
// 절대값이 같을 경우 작은 수 가 부모가 됨

func add(a: Int) {
    var index = heap.count
    heap.append(a)
    while index > 1 && abs(a) <= abs(heap[index/2]){
        if abs(a) == abs(heap[index/2]) && a > heap[index/2] {
            break
        } else {
            let temp = heap[index/2]
            heap[index/2] = a
            heap[index] = temp
            index /= 2
        }
    }
}

func pop() -> Int {

    if heap.count <= 1 {
        return 0
    }
    
    let max = heap[1]
    let index = heap.count - 1
    heap[1] = heap[index]
    heap.remove(at: index)
    
    var parent = 1
    
    while parent <= (heap.count - 1) / 2 {
        var child = parent * 2
        if(child < heap.count - 1 &&
           ( abs(heap[child]) > abs(heap[child + 1]) ||
             ( abs(heap[child]) == abs(heap[child+1]) && heap[child] > heap[child + 1])) ) {
            child += 1
        }
        if (abs(heap[parent]) < abs(heap[child]) || 
( abs(heap[parent]) == abs(heap[child]) && heap[parent] < heap[child] )) {
            break
        }
        let temp = heap[parent]
        heap[parent] = heap[child]
        heap[child] = temp
        parent = child
        
    }
    
    return max
}

let count = Int(readLine()!)!

for _ in 1...count {

    let input = Int(readLine()!)!
    if input == 0 {
        print(pop())
    } else {
        add(a: input)
    }

}

3. 2075 - N번째 큰 수

//2075
import Foundation

final class FileIO {
    private let buffer:[UInt8]
    private var index: Int = 0
    
    init(fileHandle: FileHandle = FileHandle.standardInput) {
        
        buffer = Array(try! fileHandle.readToEnd()!)+[UInt8(0)]
    }
    
    @inline(__always) private func read() -> UInt8 {
        defer { index += 1 }
        
        return buffer[index]
    }
    
    @inline(__always) func readInt() -> Int {
        var sum = 0
        var now = read()
        var isPositive = true
        
        while now == 10
                || now == 32 { now = read() }
        if now == 45 { isPositive.toggle(); now = read() }
        while now >= 48, now <= 57 {
            sum = sum * 10 + Int(now-48)
            now = read()
        }
        
        return sum * (isPositive ? 1:-1)
    }
    
}

var heap:[Int] = [0]

func push(a: Int) {
    
    var index = heap.count
    heap.append(a)
    while index > 1 && a > heap[index/2] {
        let temp = heap[index/2]
        heap[index/2] = a
        heap[index] = temp
        index /= 2
    }
    
}

func pop() -> Int {
    
    if heap.count <= 1 {
        return 0
    }
    
    let max = heap[1]
    let index = heap.count - 1
    heap[1] = heap[index]
    heap.remove(at: index)
    
    var parent = 1
    
    while parent <= (heap.count - 1) / 2 {
        var child = parent * 2
        if(child < heap.count - 1 && heap[child] < heap[child + 1]){
            child += 1
        }
        if (heap[parent] >= heap[child]) { break }
        
        let temp = heap[parent]
        heap[parent] = heap[child]
        heap[child] = temp
        parent = child
    }
    
    return max
}

let file = FileIO()
let N = file.readInt()
for _ in 1...N {
    for _ in 0..<N {
        push(a: file.readInt())
    }
}

for _ in 1..<N {
    pop()
}

print(pop())

4. 중앙값 구하기

왼쪽은 최댓값 힙

오른쪽은 최소값 힙