80 lines
1.3 KiB
Go
80 lines
1.3 KiB
Go
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package main
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import (
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aq "github.com/emirpasic/gods/v2/queues/arrayqueue"
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)
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const (
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EMPTY_CELL int = 0
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FRESH_ORANGE int = 1
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ROTTEN_ORANGE int = 2
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)
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type BFSEntry struct {
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time int
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y, x int
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}
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func orangesRotting(grid [][]int) int {
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DIRECTIONS := [][]int{
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[]int{0, 1},
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[]int{0, -1},
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[]int{1, 0},
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[]int{-1, 0},
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}
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inBounds := func(y, x int) bool {
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return y >= 0 && y < len(grid) && x >= 0 && x < len(grid[y])
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}
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countFresh := func() int {
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fresh := 0
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for _, row := range grid {
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for _, orange := range row {
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if orange == FRESH_ORANGE {
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fresh++
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}
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}
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}
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return fresh
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}
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initializeQueue := func(q *aq.Queue[BFSEntry]) {
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for y, row := range grid {
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for x, orange := range row {
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if orange != ROTTEN_ORANGE {
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continue
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}
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q.Enqueue(BFSEntry{time: 0, y: y, x: x})
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}
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}
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}
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q := aq.New[BFSEntry]()
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initializeQueue(q)
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fresh, time := countFresh(), 0
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for !q.Empty() && fresh > 0 {
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value, _ := q.Dequeue()
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for _, d := range DIRECTIONS {
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ny, nx := value.y+d[0], value.x+d[1]
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if !inBounds(ny, nx) || grid[ny][nx] != FRESH_ORANGE {
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continue
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}
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grid[ny][nx] = ROTTEN_ORANGE
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fresh--
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q.Enqueue(BFSEntry{time: value.time + 1, y: ny, x: nx})
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time = value.time + 1
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}
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}
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if fresh > 0 {
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return -1
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}
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return time
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}
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