54. Spiral Matrix

Author: vfedorovatlas

spiral-matrix/Readme.md

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+# 54. Spiral Matrix
+

spiral-matrix/main.go

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+package leecode
+
+func spiralOrder(matrix [][]int) []int {
+	ret := []int{}
+	if len(matrix) == 0 {
+		return ret
+	}
+	m := len(matrix)
+	n := len(matrix[0])
+	x := 0
+	y := 0
+	for m > 0 && n > 0 {
+		//if one row/column left, no circle can be formed
+		if m == 1 {
+			for i := 0; i < n; i++ {
+				ret = append(ret, matrix[x][y])
+				y++
+			}
+			break
+		} else if n == 1 {
+			for i := 0; i < m; i++ {
+				ret = append(ret, matrix[x][y])
+				x++
+			}
+			break
+		}
+
+		//below, process a circle
+
+		//top - move right
+		for i := 0; i < n-1; i++ {
+			ret = append(ret, matrix[x][y])
+			y++
+		}
+
+		//right - move down
+		for i := 0; i < m-1; i++ {
+			ret = append(ret, matrix[x][y])
+			x++
+		}
+
+		//bottom - move left
+		for i := 0; i < n-1; i++ {
+			ret = append(ret, matrix[x][y])
+			y--
+		}
+
+		//left - move up
+		for i := 0; i < m-1; i++ {
+			ret = append(ret, matrix[x][y])
+			x--
+		}
+
+		x++
+		y++
+		m = m - 2
+		n = n - 2
+	}
+	return ret
+}

spiral-matrix/main_test.go

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+package leecode
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestFindDiagonalOrder(t *testing.T) {
+	testCases := []struct {
+		Input  [][]int
+		Output []int
+	}{
+		{
+			Input: [][]int{
+				{1, 2, 3},
+				{4, 5, 6},
+				{7, 8, 9},
+			},
+			Output: []int{1, 2, 3, 6, 9, 8, 7, 4, 5},
+		},
+		{
+			Input: [][]int{
+				{1, 2, 3, 4},
+				{5, 6, 7, 8},
+				{9, 10, 11, 12},
+			},
+			Output: []int{1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(fmt.Sprintf("%v:%d", tc.Input, tc.Output), func(t *testing.T) {
+			actual := spiralOrder(tc.Input)
+			if !reflect.DeepEqual(actual, tc.Output) {
+				t.Errorf("expected %d, but get %d", tc.Output, actual)
+			}
+		})
+	}
+}