From 7759f2ede9a8ff32830d838b1da5ec9a46968e65 Mon Sep 17 00:00:00 2001
From: YikesHome <31678324+yikeshome@users.noreply.github.com>
Date: Wed, 30 Oct 2019 03:48:41 +0800
Subject: [PATCH] Update profile.go

---
 profiling/profile.go | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/profiling/profile.go b/profiling/profile.go
index f7beae1..e123f45 100644
--- a/profiling/profile.go
+++ b/profiling/profile.go
@@ -10,3 +10,16 @@ func Duration(invocation time.Time, name string) {
 
     log.Printf("%s lasted %s", name, elapsed)
 }
+
+func BigIntFactorial(x big.Int) *big.Int {
+    // Arguments to a defer statement is immediately evaluated and stored.
+    // The deferred function receives the pre-evaluated values when its invoked.
+    defer Duration(time.Now(), "IntFactorial")
+
+    y := big.NewInt(1)
+    for one := big.NewInt(1); x.Sign() > 0; x.Sub(x, one) {
+        y.Mul(y, x)
+    }
+
+    return x.Set(y)
+}