Codingame Solution: Power of Thor - Episode 1

Thor moves on a map which is 40 wide by 18 high. Note that the coordinates (X and Y) start at the top left! This means the most top left cell has the coordinates "X=0,Y=0" and the most bottom right one has the coordinates "X=39,Y=17".

Once the program starts you are given:

• the variable lightX: the X position of the light of power that Thor must reach.
• the variable lightY: the Y position of the light of power that Thor must reach.
• the variable initialTX: the starting X position of Thor.
• the variable initialTY: the starting Y position of Thor.

At the end of the game turn, you must output the direction in which you want Thor to go among: Each movement makes Thor move by 1 cell in the chosen direction.
 

The program must first read the initialization data from the standard input, then, in an infinite loop, provides on the standard output the instructions to move Thor.

Initialization input

Line 1: 4 integers lightXlightYinitialTXinitialTY. (lightX, lightY) indicates the position of the light. (initialTX, initialTY) indicates the initial position of Thor.

Input for a game round

Line 1: the number of remaining moves for Thor to reach the light of power: remainingTurns. You can ignore this data but you must read it.

Output for a game round

A single line providing the move to be made: N NE E SE S SW W ou NW

Constraints

0 ≤ lightX < 40
0 ≤ lightY < 18
0 ≤ initialTX < 40
0 ≤ initialTY < 18

F# Solution

open System

let token = (Console.In.ReadLine()).Split [|' '|]
let  LX = int(token.[0])
let  LY = int(token.[1])
let mutable TX = int(token.[2])
let mutable TY = int(token.[3])

while true do
    let remainingTurns = int(Console.In.ReadLine())

    if (TY > LY) then
       printf("N")
       TY <- TY - 1
    elif (TY < LY) then
       printf("S")
       TY <- TY + 1

    if (TX > LX) then
       printf("W")
       TX <- TX - 1
    elif (TX < LX) then
       printf("E")
       TX <- TX + 1

    printfn("")
    ()