[백준] 14891 톱니바퀴

 

🔒 문제

 

🧠 아이디어

 

톱니바퀴 회전 아이디어

 

시계 방향

 

반시계 방향

 

 

자료구조로 덱 사용

 

회전 방향을 결정하는 것은 index2, 6

 

 

🔑 Kotlin Code

import java.io.BufferedReader
import java.io.InputStreamReader
import java.util.*
import kotlin.collections.ArrayDeque

private fun rotateGears(gearNum: Int, gears: Array<ArrayDeque<Int>>, gearRotateDirection: IntArray) {
    when (gearRotateDirection[gearNum]) {
        -1 -> {
            gears[gearNum].addLast(gears[gearNum].removeFirst())
        }
        1 -> {
            gears[gearNum].addFirst(gears[gearNum].removeLast())
        }
        else -> {}
    }
}

private fun decideRotate(gears: Array<ArrayDeque<Int>>, leftGearNum: Int, rightGearNum: Int, isDecided: BooleanArray, gearRotateDirection: IntArray) {
    if (leftGearNum <= 0 || rightGearNum >= gears.size) return
    if (isDecided[leftGearNum] && isDecided[rightGearNum]) return

    // 같은 극이면 방향 결정 후 아무것도 할게 없음.
    if (gears[leftGearNum][2] == gears[rightGearNum][6]) {
        isDecided[leftGearNum] = true
        isDecided[rightGearNum] = true
        return
    } else {
        // 진행방향 왼쪽
        if (!isDecided[leftGearNum]) {
            gearRotateDirection[leftGearNum] = -gearRotateDirection[rightGearNum]
            isDecided[leftGearNum] = true
            decideRotate(gears, leftGearNum - 1, leftGearNum, isDecided, gearRotateDirection)
        }
        // 진행방향 오른쪽
        if (!isDecided[rightGearNum]) {
            gearRotateDirection[rightGearNum] = -gearRotateDirection[leftGearNum]
            isDecided[rightGearNum] = true
            decideRotate(gears, rightGearNum, rightGearNum + 1, isDecided, gearRotateDirection)
        }
    }
}

fun main() {
    val bufferedReader = BufferedReader(InputStreamReader(System.`in`))
    // index: gear number, value: element (0, 1)
    val gears = Array(5){ArrayDeque<Int>(8)}
    // index: gear number, value: rotate direction (-1 : counter clock wise, 0: no rotation, 1: clockwise)
    val gearRotateDirection = IntArray(5)
    // index: gear number, value: is rotation direction is decided for each round
    val isDecided = BooleanArray(5)

    for (i in 1 .. 4) {
        bufferedReader.readLine().toCharArray().map { it - '0' }.forEach { element-> gears[i].addLast(element) }
    }

    val rotateCnt = bufferedReader.readLine().toInt()

    repeat(rotateCnt) {
        val (gearNum, rotateDirection) = bufferedReader.readLine().split(" ").map(String::toInt)
        gearRotateDirection[gearNum] = rotateDirection
        isDecided[gearNum] = true
        decideRotate(gears, gearNum, gearNum + 1, isDecided, gearRotateDirection)
        decideRotate(gears, gearNum - 1, gearNum, isDecided, gearRotateDirection)

        for (gearNumber in 1 .. 4) rotateGears(gearNumber, gears, gearRotateDirection)

        Arrays.fill(gearRotateDirection, 0)
        Arrays.fill(isDecided, false)
    }

    var answer = 0

    for (idx in 1 .. 4) {
        if (gears[idx].first() == 0) continue

        // S극일 때만 점수 추가
        when(idx) {
            1 -> answer += 1
            2 -> answer += 2
            3 -> answer += 4
            4 -> answer += 8
        }
    }

    print(answer)
}