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@@ -0,0 +1,62 @@
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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/number-of-islands/?envType=study-plan-v2&envId=top-100-liked
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func numIslands(grid [][]byte) int {
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m := len(grid)
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n := len(grid[0])
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visited := make([][]bool, m)
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for i := range m {
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visited[i] = make([]bool, n)
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}
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res := 0
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type point struct {
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Row int
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Column int
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}
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queue := []point{}
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for i := range m {
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for j := range n {
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if !visited[i][j] && grid[i][j] == '1' {
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queue = append(queue, point{i, j})
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visited[i][j] = true
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res++
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}
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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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// 左侧
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if cur.Column > 0 && !visited[cur.Row][cur.Column-1] && grid[cur.Row][cur.Column-1] == '1' {
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queue = append(queue, point{cur.Row, cur.Column - 1})
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visited[cur.Row][cur.Column-1] = true
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}
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// 右侧
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if cur.Column+1 < n && !visited[cur.Row][cur.Column+1] && grid[cur.Row][cur.Column+1] == '1' {
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queue = append(queue, point{cur.Row, cur.Column + 1})
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visited[cur.Row][cur.Column+1] = true
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}
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// 上侧
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if cur.Row > 0 && !visited[cur.Row-1][cur.Column] && grid[cur.Row-1][cur.Column] == '1' {
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queue = append(queue, point{cur.Row - 1, cur.Column})
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visited[cur.Row-1][cur.Column] = true
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}
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// 下侧
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if cur.Row+1 < m && !visited[cur.Row+1][cur.Column] && grid[cur.Row+1][cur.Column] == '1' {
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queue = append(queue, point{cur.Row + 1, cur.Column})
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visited[cur.Row+1][cur.Column] = true
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}
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}
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}
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}
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return res
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}
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func Test(t *testing.T) {
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input := [][]byte{{'1', '1', '1'}, {'0', '1', '0'}, {'1', '1', '1'}}
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fmt.Println(numIslands(input))
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}
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@@ -0,0 +1,130 @@
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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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@@ -0,0 +1,39 @@
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package top100liked
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// https://leetcode.cn/problems/course-schedule/?envType=study-plan-v2&envId=top-100-liked
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import "slices"
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func canFinish(numCourses int, prerequisites [][]int) bool {
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adjacencyList := make([][]int, numCourses)
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for _, prerequisit := range prerequisites {
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from, to := prerequisit[1], prerequisit[0]
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adjacencyList[from] = append(adjacencyList[from], to)
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}
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state := make([]int, numCourses)
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var hasCycle func(int) bool
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hasCycle = func(node int) bool {
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if state[node] == 1 {
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return true
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}
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if state[node] == 2 {
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return false
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}
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state[node] = 1
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if slices.ContainsFunc(adjacencyList[node], hasCycle) {
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return true
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}
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state[node] = 2
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return false
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}
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for i := 0; i < numCourses; i++ {
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if hasCycle(i) {
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return false
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}
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}
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return true
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}
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@@ -0,0 +1,67 @@
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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/implement-trie-prefix-tree/?envType=study-plan-v2&envId=top-100-liked
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type Node struct {
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children [26]*Node
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isEnd bool
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}
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type Trie struct {
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root *Node
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}
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func Constructor() Trie {
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return Trie{root: &Node{}}
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}
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func (this *Trie) Insert(word string) {
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cur := this.root
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for i := 0; i < len(word); i++ {
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idx := word[i] - 'a'
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if cur.children[idx] == nil {
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cur.children[idx] = &Node{}
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}
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cur = cur.children[idx]
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}
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cur.isEnd = true
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}
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func (this *Trie) Search(word string) bool {
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cur := this.root
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for i := 0; i < len(word); i++ {
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idx := word[i] - 'a'
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if cur.children[idx] == nil {
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return false
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}
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cur = cur.children[idx]
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}
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return cur.isEnd
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}
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func (this *Trie) StartsWith(prefix string) bool {
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cur := this.root
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for i := 0; i < len(prefix); i++ {
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idx := prefix[i] - 'a'
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if cur.children[idx] == nil {
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return false
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}
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cur = cur.children[idx]
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}
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return true
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}
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func Test(t *testing.T) {
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trie := Constructor()
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trie.Insert("apple")
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fmt.Println(trie.Search("apple")) // 返回 True
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fmt.Println(trie.Search("app")) // 返回 False
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fmt.Println(trie.StartsWith("app")) // 返回 True
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trie.Insert("app")
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fmt.Println(trie.Search("app")) // 返回 True
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}
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@@ -0,0 +1,41 @@
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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/permutations?envType=study-plan-v2&envId=top-100-liked
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func permute(nums []int) [][]int {
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l := len(nums)
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fact := 1
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for i := 2; i <= l; i++ {
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fact *= i
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}
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res := make([][]int, 0, fact)
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var helper func(nums []int, used []bool, r []int)
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helper = func(nums []int, used []bool, r []int) {
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for i, v := range used {
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if !v {
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used[i] = true
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r = append(r, nums[i])
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if len(r) == l {
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cp := make([]int, l)
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copy(cp, r)
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res = append(res, cp)
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} else {
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helper(nums, used, r)
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}
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r = r[:len(r)-1]
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used[i] = false
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}
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}
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}
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helper(nums, make([]bool, l), make([]int, 0))
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return res
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}
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func Test(t *testing.T) {
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fmt.Printf("%+v", permute([]int{5, 4, 6, 2}))
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}
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