add kotlin solution for 1958 - Check If Move Is Legal

kotlin/1958-check-if-move-is-legal.kt

@@ -0,0 +1,95 @@
+// recursive solution
+class Solution {
+ fun checkMove(board: Array<CharArray>, rMove: Int, cMove: Int, color: Char): Boolean {
+ board[rMove][cMove] = color
+
+ val rowColumDirections = arrayOf(
+ intArrayOf(0, 1),
+ intArrayOf(0, -1),
+ intArrayOf(1, 0),
+ intArrayOf(-1, 0),
+ intArrayOf(1, 1),
+ intArrayOf(-1, -1),
+ intArrayOf(1, -1),
+ intArrayOf(-1, 1)
+ )
+
+ fun isValidCell(row: Int, column: Int) = row in board.indices &&
+ column in board[row].indices &&
+ board[row][column] != EMPTY_CELL &&
+ board[row][column] != VISITED_CELL
+
+ fun dfs(
+ startRow: Int,
+ startColumn: Int,
+ rowDir: Int,
+ columnDir: Int,
+ cellsInCurrentPath: Int
+ ): Boolean {
+ if (board[startRow][startColumn] == color) {
+ board[startRow][startColumn] = VISITED_CELL
+ return cellsInCurrentPath >= 2 // there must be 2 other nodes, not including the current node
+ }
+ board[startRow][startColumn] = VISITED_CELL
+ val newRow = startRow + rowDir
+ val newColumn = startColumn + columnDir
+ if (!isValidCell(newRow, newColumn)) return false
+ return dfs(newRow, newColumn, rowDir, columnDir, cellsInCurrentPath + 1)
+ }
+
+ for ((rowDir, colDir) in rowColumDirections) {
+ val newRow = rMove + rowDir
+ val newColumn = cMove + colDir
+ if (!isValidCell(newRow, newColumn)) continue
+ if (dfs(newRow, newColumn, rowDir, colDir, 1)) return true
+ }
+ return false
+ }
+
+ companion object {
+ private const val VISITED_CELL = '|'
+ private const val EMPTY_CELL = '.'
+ }
+}
+
+// Iterative Solution
+class Solution {
+
+ fun checkMove(board: Array<CharArray>, rMove: Int, cMove: Int, color: Char): Boolean {
+ val rowColumDirections = arrayOf(
+ intArrayOf(0, 1),
+ intArrayOf(0, -1),
+ intArrayOf(1, 0),
+ intArrayOf(-1, 0),
+ intArrayOf(1, 1),
+ intArrayOf(-1, -1),
+ intArrayOf(1, -1),
+ intArrayOf(-1, 1)
+ )
+
+ fun isValidCell(row: Int, column: Int) = row in board.indices &&
+ column in board[row].indices &&
+ board[row][column] != EMPTY_CELL
+
+ fun checkIfValidInDirection(rowDir: Int, colDir: Int): Boolean {
+ var currentRow = rMove + rowDir
+ var currentColumn = cMove + colDir
+ var numberOfCellsInPath = 1
+ while (isValidCell(currentRow, currentColumn) && board[currentRow][currentColumn] != color) {
+ numberOfCellsInPath++
+ currentRow += rowDir
+ currentColumn += colDir
+ }
+ return isValidCell(currentRow, currentColumn) && numberOfCellsInPath >= 2
+ }
+
+ for ((rowDir, colDir) in rowColumDirections) {
+ if (checkIfValidInDirection(rowDir, colDir)) return true
+ }
+ return false
+ }
+
+ companion object {
+ private const val EMPTY_CELL = '.'
+ }
+}