67

2 files changed, 75 insertions, 0 deletions

diff --git a/67/go.mod b/67/go.mod
new file mode 100644
index 0000000..4b89718
--- /dev/null
+++ b/67/go.mod
@@ -0,0 +1,3 @@
+module 67
+
+go 1.19
diff --git a/67/main.go b/67/main.go
new file mode 100644
index 0000000..4cafdcf
--- /dev/null
+++ b/67/main.go
@@ -0,0 +1,72 @@
+package main
+
+import "fmt"
+
+func addBinary(a string, b string) string {
+	var long string
+	var short string
+	var count int
+	carry := false
+
+	if len(a) >= len(b) {
+		long = a
+		short = b
+	} else {
+		long = b
+		short = a
+	}
+
+	result := make([]byte, len(long)+1)
+
+	for i := len(long) - 1; i >= 0; i-- {
+		if long[i] == '1' {
+			count++
+		}
+
+		if len(short)-(len(long)-i) >= 0 {
+			if short[len(short)-(len(long)-i)] == '1' {
+				count++
+			}
+		}
+
+		if carry {
+			count++
+		}
+
+		switch count {
+		case 0:
+			result[i+1] = '0'
+			carry = false
+		case 1:
+			result[i+1] = '1'
+			carry = false
+		case 2:
+			result[i+1] = '0'
+			carry = true
+		case 3:
+			result[i+1] = '1'
+			carry = true
+		}
+
+		count = 0
+	}
+	if carry {
+		result[0] = '1'
+	}
+
+	// fmt.Println(result)
+	if result[0] == 0 {
+		return string(result[1:])
+	} else {
+		return string(result)
+	}
+}
+
+func main() {
+	fmt.Println(addBinary("11", "1"))
+	fmt.Println(addBinary("1010", "1011"))
+	fmt.Println(addBinary("0111", "0111"))
+	fmt.Println(addBinary("0", "0"))
+	fmt.Println(addBinary("10", "0"))
+	fmt.Println(addBinary("10", "1"))
+}