Add: plus_one

Author: Openset

problems/plus-one/plus_one.go

@@ -1 +1,16 @@
 package plus_one
+
+func plusOne(digits []int) []int {
+	l := len(digits)
+	for i := l - 1; i >= 0; i-- {
+		if digits[i] < 9 {
+			digits[i]++
+			return digits
+		}
+		digits[i] = 0
+	}
+	if digits[0] == 0 {
+		digits = append([]int{1}, digits...)
+	}
+	return digits
+}

problems/plus-one/plus_one_test.go

@@ -1 +1,39 @@
 package plus_one
+
+import (
+	"reflect"
+	"testing"
+)
+
+type caseType struct {
+	input    []int
+	expected []int
+}
+
+func TestPlusOne(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    []int{1, 2, 3},
+			expected: []int{1, 2, 4},
+		},
+		{
+			input:    []int{4, 3, 2, 1},
+			expected: []int{4, 3, 2, 2},
+		},
+		{
+			input:    []int{1, 2, 9, 9},
+			expected: []int{1, 3, 0, 0},
+		},
+		{
+			input:    []int{9, 9},
+			expected: []int{1, 0, 0},
+		},
+	}
+
+	for _, tc := range tests {
+		output := plusOne(tc.input)
+		if !reflect.DeepEqual(output, tc.expected) {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}