feature/874: add 874 solution

leetcode/0874.Walking-Robot-Simulation/Walking Robot Simulation.go

@@ -0,0 +1,38 @@
+package leetcode
+
+func robotSim(commands []int, obstacles [][]int) int {
+	m := make(map[[2]int]struct{})
+	for _, v := range obstacles {
+		if len(v) != 0 {
+			m[[2]int{v[0], v[1]}] = struct{}{}
+		}
+	}
+	directX := []int{0, 1, 0, -1}
+	directY := []int{1, 0, -1, 0}
+	direct, x, y := 0, 0, 0
+	result := 0
+	for _, c := range commands {
+		if c == -2 {
+			direct = (direct + 3) % 4
+			continue
+		}
+		if c == -1 {
+			direct = (direct + 1) % 4
+			continue
+		}
+		for ; c > 0; c-- {
+			nextX := x + directX[direct]
+			nextY := y + directY[direct]
+			if _, ok := m[[2]int{nextX, nextY}]; ok {
+				break
+			}
+			tmpResult := nextX*nextX + nextY*nextY
+			if tmpResult > result {
+				result = tmpResult
+			}
+			x = nextX
+			y = nextY
+		}
+	}
+	return result
+}