update

oj/hulu-2019-interview/main.go

@@ -0,0 +1,73 @@
+// The exponential of 11
+
+// 3fsv3 - collabedit.com
+
+package main
+
+import "fmt"
+
+// Node ...
+type Node struct {
+	val  int
+	next *Node
+}
+
+func reverse(head *Node) *Node {
+	if head == nil || head.next == nil {
+		return head
+	}
+	dummy := Node{-1, nil}
+	tail := head.next
+	for tail != nil {
+		tmp := tail.next
+		tail.next = dummy.next
+		dummy.next = tail
+		tail = tmp
+	}
+	head.next = dummy.next
+	return head
+}
+
+func pow(n int) string {
+	base := []byte{'1', '1'}
+	res := []byte{'1'}
+	for n != 0 {
+		if n&1 == 1 {
+			res = mul(res, base)
+		}
+		base = mul(base, base)
+		n >>= 1
+	}
+	for l, r := 0, len(res)-1; l < r; l, r = l+1, r-1 {
+		res[l], res[r] = res[r], res[l]
+	}
+	return string(res)
+}
+
+func mul(a, b []byte) []byte {
+	m, n := len(a), len(b)
+	c := make([]byte, m+n)
+	for i := range c {
+		c[i] = '0'
+	}
+	for i := 0; i < m; i++ {
+		for j := 0; j < n; j++ {
+			res := (a[i] - '0') * (b[j] - '0')
+			c[i+j] += res
+		}
+	}
+	mod, i := 0, 0
+	for ; i < len(c); i++ {
+		c[i] += byte(mod)
+		mod = int(c[i]-'0') / 10
+		c[i] = byte(int(c[i]-'0')%10 + '0')
+		if c[i] == '0' && mod == 0 {
+			break
+		}
+	}
+	return c[:i]
+}
+
+func main() {
+	fmt.Println(pow(6))
+}