Create 0778-swim-in-rising-water.kt

kotlin/0778-swim-in-rising-water.kt

@@ -0,0 +1,27 @@
+class Solution {
+ fun swimInWater(grid: Array<IntArray>): Int {
+ val visited = Array<BooleanArray>(grid.size){ BooleanArray(grid[0].size) }
+ val minHeap = PriorityQueue<IntArray>{ a: IntArray, b: IntArray -> a[0] - b[0] } //[height, r, c]
+ val directions = arrayOf(intArrayOf(1,-1,0,0),intArrayOf(0,0,1,-1))
+ minHeap.add(intArrayOf(grid[0][0],0,0)) //startpos
+ while(!minHeap.isEmpty()){
+ val (h,r,c) = minHeap.poll()
+ visited[r][c] = true
+ if(r == grid.size-1 && c == grid[0].size-1)
+ return h
+ for(i in 0..3){
+ val nextR = r + directions[0][i]
+ val nextC = c + directions[1][i]
+ if(isValid(grid,visited,nextR, nextC))
+ minHeap.add(intArrayOf(maxOf(h,grid[nextR][nextC]),nextR,nextC))
+ }
+ }
+ return -1
+ }
+ private fun isValid(
+ grid: Array<IntArray>,
+ visited: Array<BooleanArray>,
+ r: Int,
+ c: Int
+ ) = r >= 0 && c >= 0 && r < grid.size && c < grid[0].size && visited[r][c] == false
+}