Add: Binary Prefix Divisible By 5

Author: openset

problems/binary-prefix-divisible-by-5/binary_prefix_divisible_by_5.go

@@ -0,0 +1,10 @@
+package binary_prefix_divisible_by_5
+
+func prefixesDivBy5(A []int) []bool {
+	ans, v := make([]bool, len(A)), 0
+	for i, b := range A {
+		v = (v<<1 + b) % 5
+		ans[i] = v == 0
+	}
+	return ans
+}

problems/binary-prefix-divisible-by-5/binary_prefix_divisible_by_5_test.go

@@ -0,0 +1,42 @@
+package binary_prefix_divisible_by_5
+
+import (
+	"reflect"
+	"testing"
+)
+
+type caseType struct {
+	input    []int
+	expected []bool
+}
+
+func TestPrefixesDivBy5(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    []int{0, 1, 1},
+			expected: []bool{true, false, false},
+		},
+		{
+			input:    []int{1, 1, 1},
+			expected: []bool{false, false, false},
+		},
+		{
+			input:    []int{0, 1, 1, 1, 1, 1},
+			expected: []bool{true, false, false, false, true, false},
+		},
+		{
+			input:    []int{1, 1, 1, 0, 1},
+			expected: []bool{false, false, false, false, false},
+		},
+		{
+			input:    []int{1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0},
+			expected: []bool{false, false, true, false, false, false, false, false, false, false, true, true, true, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, false, false, true, false, false, true, false, false, true, true, true, true, true, true, true, false, false, true, false, false, false, false, true, true},
+		},
+	}
+	for _, tc := range tests {
+		output := prefixesDivBy5(tc.input)
+		if !reflect.DeepEqual(output, tc.expected) {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}