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| object WordSerach {
def main(args: Array[String]): Unit = {
val board = Array[Array[Char]](
Array('A', 'B', 'C', 'E')
)
println(exist(board, "BC"))
println(exist(board, "ABCCED"))
println(exist(board, "ABCB"))
}
def exist(board: Array[Array[Char]], word: String): Boolean = {
val m = board.length
if (m == 0) return false
val n = board(0).length
val selected = new mutable.HashSet[(Int, Int)]()
for (i <- 0 until m) {
for (j <- 0 until n) {
if (board(i)(j) == word.charAt(0)) {
selected.clear()
val pos = (i, j)
selected += pos
if (dfs(board, selected, pos, word, 1)) {
return true
}
}
}
}
false
}
def dfs(board: Array[Array[Char]], selected: mutable.HashSet[(Int, Int)], pos: (Int, Int), word: String, index: Int): Boolean = {
if (index == word.length) {
return true
}
Array[(Int, Int)](
(pos._1, pos._2 - 1),
(pos._1 - 1, pos._2),
(pos._1, pos._2 + 1),
(pos._1 + 1, pos._2)
).foreach(a => {
if (0 <= a._1 && a._1 < board.length && 0 <= a._2 && a._2 < board(0).length) {
if (!selected.contains(a) && board(a._1)(a._2) == word.charAt(index)) {
selected += a
if (dfs(board, selected, a, word, index + 1)) {
return true
}
selected -= a
}
}
})
false
}
}
|