Add: Ransom Note

problems/ransom-note/ransom_note.go

@@ -1 +1,15 @@
 package ransom_note
+
+func canConstruct(ransomNote string, magazine string) bool {
+	var m [128]int
+	for _, c := range magazine {
+		m[c]++
+	}
+	for _, c := range ransomNote {
+		m[c]--
+		if m[c] < 0 {
+			return false
+		}
+	}
+	return true
+}

problems/ransom-note/ransom_note_test.go

@@ -1 +1,35 @@
 package ransom_note
+
+import "testing"
+
+type caseType struct {
+	ransom   string
+	magazine string
+	expected bool
+}
+
+func TestCanConstruct(t *testing.T) {
+	tests := [...]caseType{
+		{
+			ransom:   "a",
+			magazine: "b",
+			expected: false,
+		},
+		{
+			ransom:   "aa",
+			magazine: "ab",
+			expected: false,
+		},
+		{
+			ransom:   "aa",
+			magazine: "aab",
+			expected: true,
+		},
+	}
+	for _, tc := range tests {
+		output := canConstruct(tc.ransom, tc.magazine)
+		if output != tc.expected {
+			t.Fatalf("input: %v %v, output: %v, expected: %v", tc.ransom, tc.magazine, output, tc.expected)
+		}
+	}
+}