routine

26/05/1559.go

@@ -0,0 +1,57 @@
+package A
+
+type node1559 struct {
+	x, y   int
+	px, py int
+}
+
+func containsCycle(grid [][]byte) bool {
+	m := len(grid)
+	n := len(grid[0])
+	if m < 2 || n < 2 {
+		return false
+	}
+
+	visited := make([][]bool, m)
+	for i := range visited {
+		visited[i] = make([]bool, n)
+	}
+
+	dirs := [][2]int{{0, -1}, {0, 1}, {-1, 0}, {1, 0}}
+
+	for i := 0; i < m; i++ {
+		for j := 0; j < n; j++ {
+			if visited[i][j] {
+				continue
+			}
+
+			visited[i][j] = true
+			stack := []node1559{{x: i, y: j, px: -1, py: -1}}
+
+			for len(stack) > 0 {
+				top := stack[len(stack)-1]
+				stack = stack[:len(stack)-1]
+
+				for _, dir := range dirs {
+					nx := top.x + dir[0]
+					ny := top.y + dir[1]
+					if nx < 0 || nx >= m || ny < 0 || ny >= n {
+						continue
+					}
+					if grid[nx][ny] != grid[top.x][top.y] {
+						continue
+					}
+
+					if !visited[nx][ny] {
+						visited[nx][ny] = true
+						stack = append(stack, node1559{x: nx, y: ny, px: top.x, py: top.y})
+					} else if nx != top.px || ny != top.py {
+						return true
+					}
+				}
+			}
+		}
+	}
+
+	return false
+}