codingame - Skynet: the Chasm

main.go

package main

import (
    "fmt"
    "os"
    "strconv"
)

type Bike struct {
    // speed of the bike
    Speed int
    // position on the road
    Position int
    // length of road before gap
    Road int
    // instruction
    Order int
    // gap size
    Gap int
    // platform length
    Platform int
    // turn
    Turn int
}

// command
var C map[int]string

func main() {
    // R: the length of the road before the gap.
    var R int
    fmt.Scan(&R)
    
    // G: the length of the gap.
    var G int
    fmt.Scan(&G)
    
    // L: the length of the landing platform.
    var L int
    fmt.Scan(&L)
    
    // S: the motorbike's speed.
    var S int
  
    // X: the position on the road of the motorbike.
    var X int
    
    C = map[int]string{
        -1: "SLOW",
        0: "WAIT",
        1: "SPEED",
        2: "JUMP",
    }

    // initialize the Terminator
    terminator := Bike{S, X, R, 1, G, L, 1}

    // game loop
    for {
        // update the speed
        fmt.Scan(&S)
        terminator.Speed = S
        
        // update the position
        fmt.Scan(&X)
        terminator.Position = X
        
        terminator.Update()
        
        // fmt.Fprintln(os.Stderr, "Debug messages...")
    
        fmt.Println(C[terminator.Order]) // A single line containing one of 4 keywords: SPEED, SLOW, JUMP, WAIT.
    }
}

func (b *Bike) Update() {
    // update the road length before the gap
    if b.Turn > 1 {
        b.Road = b.Road - b.Speed
    }
    b.Turn++

    fmt.Fprintln(os.Stderr, "ROAD: " + strconv.Itoa(b.Road-1))
    fmt.Fprintln(os.Stderr, "GAP:  " + strconv.Itoa(b.Gap))

    /**
     * if the remaining road a multiple of gap
     * if the remaining road is greater than the speed -> speed
     * if the remaining road is equals to 1 -> jump
     * if the gap is behind us -> slow
     */
    lGap := b.Gap+1
    
    if b.Road > 0 {
        if b.Road < lGap {
            b.Order = 2
        } else {
            if b.Speed < lGap {
                b.Order = 1
            } else if b.Speed == lGap {
                b.Order = 0
            } else {
                b.Order = -1
            }
        }
    } else {
        b.Order = -1 // slow down after the jump
    }
	
    fmt.Fprintln(os.Stderr, "SPEED: " + strconv.Itoa(b.Speed) + "; POSITION: " + strconv.Itoa(b.Position))
    fmt.Fprintln(os.Stderr, "ORDER: [" + strconv.Itoa(b.Order) + "] => " + C[b.Order])
}