/* Created for code golf challenge: https://codegolf.stackexchange.com/questions/163577 Knight Distance In Chess, a Knight on grid (x, y) may move to (x-2, y-1), (x-2, y+1), (x-1, y-2), (x-1, y+2), (x+1, y-2), (x+1, y+2), (x+2, y-1), (x+2, y+1) in one step. Imagine an infinite chessboard with only a Knight on (0, 0): How many steps is required for moving a Knight from (0, 0) to (tx, ty)? Inputs Two integers: tx, ty; -100 < tx < 100, -100 < ty < 100 Output Minimal steps needed to move a Knight from (0, 0) to (tx, ty). Rules code golf Testcases x y -> out 0, 0 -> 0 0, 1 -> 3 0, 2 -> 2 1, 1 -> 2 1, 2 -> 1 3, 3 -> 2 4, 0 -> 2 42, 22 -> 22 84, 73 -> 53 45, 66 -> 37 99, 99 -> 66 -45, -91 -> 46 -81, 1 -> 42 11, -2 -> 7 Related OEIS Here are some OEIS for further reading A018837: Number of steps for knight to reach (n,0) on infinite chessboard. A018838: Number of steps for knight to reach (n,n) on infinite chessboard. A065775: Array T read by diagonals: T(i,j)=least number of knight's moves on a chessboard (infinite in all directions) needed to move from (0,0) to (i,j). A183041: Least number of knight's moves from (0,0) to (n,1) on infinite chessboard. 140 bytes */ fun s(x:Int,y:Int):Int=if(y<0)s(x,-y)else if(x) { // Test cases. val cases = arrayOf( arrayOf(0, 0, 0), arrayOf(0, 1, 3), arrayOf(0, 2, 2), arrayOf(1, 1, 2), arrayOf(1, 2, 1), arrayOf(3, 3, 2), arrayOf(4, 0, 2), arrayOf(42, 22, 22), arrayOf(84, 73, 53), arrayOf(45, 66, 37), arrayOf(99, 99, 66), arrayOf(-45, -91, 46), arrayOf(-81, 1, 42), arrayOf(11, -2, 7), arrayOf(3, 1, 2), arrayOf(4, 3, 3)) // For each test, perform it and print the result. for (test in cases) { val result = s(test[0], test[1]) println("[${test[0]}, ${test[1]}]="+ "${result} ${result == test[2]}") } // for } // main

knight cg