Add: Climbing Stairs

problems/climbing-stairs/climbing_stairs.go

@@ -1 +1,12 @@
 package climbing_stairs
+
+func climbStairs(n int) int {
+	if n == 1 {
+		return 1
+	}
+	first, second := 1, 2
+	for i := 3; i <= n; i++ {
+		first, second = second, first+second
+	}
+	return second
+}

problems/climbing-stairs/climbing_stairs_test.go

@@ -1 +1,31 @@
 package climbing_stairs
+
+import "testing"
+
+type caseType struct {
+	input    int
+	expected int
+}
+
+func TestClimbStairs(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    1,
+			expected: 1,
+		},
+		{
+			input:    2,
+			expected: 2,
+		},
+		{
+			input:    3,
+			expected: 3,
+		},
+	}
+	for _, tc := range tests {
+		output := climbStairs(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}