Merge pull request #1010 from 0xff-dev/1391

Add solution and test-cases for problem 1391

leetcode/1301-1400/1391.Check-if-There-is-a-Valid-Path-in-a-Grid/README.md

@@ -0,0 +1,54 @@
+# [1391. Check if There is a Valid Path in a Grid][title]
+
+## Description
+You are given an `m x n` `grid`. Each cell of `grid` represents a street. The street of `grid[i][j]` can be:
+
+- `1` which means a street connecting the left cell and the right cell.
+- `2` which means a street connecting the upper cell and the lower cell.
+- `3` which means a street connecting the left cell and the lower cell.
+- `4` which means a street connecting the right cell and the lower cell.
+- `5` which means a street connecting the left cell and the upper cell.
+- `6` which means a street connecting the right cell and the upper cell.
+
+![1](./1.png)
+
+You will initially start at the street of the upper-left cell `(0, 0)`. A valid path in the grid is a path that starts from the upper left cell `(0, 0)` and ends at the bottom-right cell `(m - 1, n - 1)`. **The path should only follow the streets**.
+
+**Notice** that you are **not allowed** to change any street.
+
+Return `true` if there is a valid path in the grid or `false` otherwise.
+
+**Example 1:**  
+
+![e1](./e1.png)
+
+```
+Input: grid = [[2,4,3],[6,5,2]]
+Output: true
+Explanation: As shown you can start at cell (0, 0) and visit all the cells of the grid to reach (m - 1, n - 1).
+```
+
+**Example 2:**  
+
+![e2](./e1.png)
+
+```
+Input: grid = [[1,2,1],[1,2,1]]
+Output: false
+Explanation: As shown you the street at cell (0, 0) is not connected with any street of any other cell and you will get stuck at cell (0, 0)
+```
+
+**Example 3:**
+
+```
+Input: grid = [[1,1,2]]
+Output: false
+Explanation: You will get stuck at cell (0, 1) and you cannot reach cell (0, 2).
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/check-if-there-is-a-valid-path-in-a-grid
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/1301-1400/1391.Check-if-There-is-a-Valid-Path-in-a-Grid/Solution.go

@@ -1,5 +1,113 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+var dirFn = [6]func(int, int, [][]int) [][2]int{
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x, y-1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 4 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x, y+1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 3 || grid[nx][ny] == 5) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x-1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 3 || grid[nx][ny] == 4) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x+1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 5 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x, y-1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 4 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x+1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 5 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x, y+1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 3 || grid[nx][ny] == 5) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x+1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 5 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x, y-1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 4 || grid[nx][ny] == 6) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x-1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 3 || grid[nx][ny] == 4) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+	func(x, y int, grid [][]int) [][2]int {
+		m, n := len(grid), len(grid[0])
+		res := make([][2]int, 0)
+
+		nx, ny := x, y+1
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 1 || grid[nx][ny] == 3 || grid[nx][ny] == 5) {
+			res = append(res, [2]int{nx, ny})
+		}
+		nx, ny = x-1, y
+		if !(nx < 0 || nx >= m || ny < 0 || ny >= n) && (grid[nx][ny] == 2 || grid[nx][ny] == 3 || grid[nx][ny] == 4) {
+			res = append(res, [2]int{nx, ny})
+		}
+		return res
+	},
+}
+
+func Solution(grid [][]int) bool {
+	m, n := len(grid)-1, len(grid[0])-1
+	q := [][2]int{{0, 0}}
+	v := make(map[[2]int]struct{})
+	v[[2]int{0, 0}] = struct{}{}
+	for len(q) > 0 {
+		nq := make([][2]int, 0)
+		for _, pos := range q {
+			x, y := pos[0], pos[1]
+			if x == m && y == n {
+				return true
+			}
+			for _, next := range dirFn[grid[x][y]-1](x, y, grid) {
+				if _, ok := v[next]; ok {
+					continue
+				}
+				nq = append(nq, next)
+				v[next] = struct{}{}
+			}
+		}
+		q = nq
+	}
+	return false
 }

leetcode/1301-1400/1391.Check-if-There-is-a-Valid-Path-in-a-Grid/Solution_test.go

@@ -10,12 +10,12 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs [][]int
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", [][]int{{2, 4, 3}, {6, 5, 2}}, true},
+		{"TestCase2", [][]int{{1, 2, 1}, {1, 2, 1}}, false},
+		{"TestCase3", [][]int{{1, 1, 2}}, false},
 	}
 
 	//	开始测试
@@ -30,10 +30,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }