131 lines
2.5 KiB
Go
131 lines
2.5 KiB
Go
package top100liked
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import (
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"fmt"
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"testing"
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)
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// https://leetcode.cn/problems/rotting-oranges/?envType=study-plan-v2&envId=top-100-liked
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type point struct {
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Row int
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Col int
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}
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// AC，成绩不错，但是写的比较复杂
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// func getFreshOrangesAround(grid [][]int, p point) []point {
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// m, n := len(grid), len(grid[0])
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// r, c := p.Row, p.Col
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// res := []point{}
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// if r > 0 && grid[r-1][c] == 1 {
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// res = append(res, point{r - 1, c})
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// }
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// if r < m-1 && grid[r+1][c] == 1 {
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// res = append(res, point{r + 1, c})
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// }
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// if c > 0 && grid[r][c-1] == 1 {
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// res = append(res, point{r, c - 1})
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// }
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// if c < n-1 && grid[r][c+1] == 1 {
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// res = append(res, point{r, c + 1})
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// }
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// return res
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// }
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// func orangesRotting(grid [][]int) int {
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// m := len(grid)
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// n := len(grid[0])
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// queue := []point{}
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// minutes := 0
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// for row := range m {
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// for col := range n {
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// if grid[row][col] == 2 {
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// queue = append(queue, point{row, col})
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// minutes = -1
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// }
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// }
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// }
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// for len(queue) > 0 {
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// batch := []point{}
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// for len(queue) > 0 {
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// cur := queue[0]
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// queue = queue[1:]
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// freshOranges := getFreshOrangesAround(grid, cur)
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// for _, p := range freshOranges {
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// grid[p.Row][p.Col] = 2
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// }
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// batch = append(batch, freshOranges...)
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// }
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// minutes++
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// queue = batch
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// }
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// for row := range m {
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// for col := range n {
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// if grid[row][col] == 1 {
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// return -1
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// }
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// }
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// }
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// return minutes
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// }
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func orangesRotting(grid [][]int) int {
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m, n := len(grid), len(grid[0])
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queue := []point{}
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fresh := 0
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for r := range m {
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for c := range n {
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switch grid[r][c] {
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case 2:
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queue = append(queue, point{r, c})
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case 1:
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fresh++
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}
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}
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}
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if fresh == 0 {
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return 0
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}
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minutes := -1
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dirs := []point{{-1, 0}, {1, 0}, {0, -1}, {0, 1}}
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for len(queue) > 0 {
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size := len(queue)
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for range size {
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cur := queue[0]
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queue = queue[1:]
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for _, d := range dirs {
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nr, nc := cur.Row+d.Row, cur.Col+d.Col
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if nr >= 0 && nr < m && nc >= 0 && nc < n && grid[nr][nc] == 1 {
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grid[nr][nc] = 2
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fresh--
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queue = append(queue, point{nr, nc})
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}
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}
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}
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minutes++
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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 minutes
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}
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func Test1(t *testing.T) {
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input := [][]int{{2, 1, 1}, {1, 1, 0}, {0, 1, 1}}
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fmt.Println(orangesRotting(input))
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}
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func Test2(t *testing.T) {
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input := [][]int{{2, 1, 1}, {0, 1, 1}, {1, 0, 1}}
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fmt.Println(orangesRotting(input))
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}
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func Test3(t *testing.T) {
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input := [][]int{{0, 2}}
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fmt.Println(orangesRotting(input))
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}
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