feat(leetcode): add No.1091

Author: mickey0524

1091.Shortest-Path-in-Binary-Matrix.go

@@ -0,0 +1,64 @@
+// https://leetcode.com/problems/shortest-path-in-binary-matrix/
+//
+// algorithms
+// Medium (35.69%)
+// Total Accepted:    3,868
+// Total Submissions: 10,837
+// beats 100.0% of golang submissions
+
+package leetcode
+
+type point struct {
+	i   int
+	j   int
+	sum int
+}
+
+func shortestPathBinaryMatrix(grid [][]int) int {
+	length := len(grid)
+	delta := [][]int{{1, 0}, {-1, 0}, {0, 1}, {0, -1}, {-1, -1}, {-1, 1}, {1, -1}, {1, 1}}
+
+	if grid[0][0] == 1 {
+		return -1
+	}
+
+	if length == 1 {
+		return 1
+	}
+
+	var q []point
+	q = append(q, point{
+		i:   0,
+		j:   0,
+		sum: 1,
+	})
+
+	for len(q) > 0 {
+		curP := q[0]
+		q = q[1:]
+		for _, d := range delta {
+			if checkPosition(curP.i+d[0], curP.j+d[1], length, grid) {
+				nextI, nextJ := curP.i+d[0], curP.j+d[1]
+				if nextI == length-1 && nextJ == length-1 {
+					return curP.sum + 1
+				}
+				q = append(q, point{
+					i:   nextI,
+					j:   nextJ,
+					sum: curP.sum + 1,
+				})
+				grid[nextI][nextJ] = 1
+			}
+		}
+	}
+
+	return -1
+}
+
+func checkPosition(i, j, length int, grid [][]int) bool {
+	if i < 0 || i >= length || j < 0 || j >= length || grid[i][j] == 1 {
+		return false
+	}
+
+	return true
+}