From 3fe8523ac7ebb7bdd876e5a961788b534eb82aa4 Mon Sep 17 00:00:00 2001
From: Voile <voileexperiments@gmail.com>
Date: Tue, 5 Mar 2019 11:00:46 +0800
Subject: [PATCH] fix all prime check fns (#1021)
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`n < 2`全部返回1是甚麼鬼
---
 docs/math/prime.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/math/prime.md b/docs/math/prime.md
index 7fd9e77a..02a76eb8 100644
--- a/docs/math/prime.md
+++ b/docs/math/prime.md
@@ -14,6 +14,7 @@
 
 ```c++
 bool isPrime(a) {
+  if (a < 2) return 0;
   for (int i = 2; i < a; ++i)
     if (a % i == 0) return 0;
   return 1;
@@ -30,6 +31,7 @@ bool isPrime(a) {
 
 ```c++
 bool isPrime(a) {
+  if (a < 2) return 0;
   for (int i = 2; i * i <= a; ++i)
     if (a % i) return 0;
   return 1;
@@ -48,6 +50,7 @@ Miller-Rabin 素性测试（Miller–Rabin primality test）是进阶的素数
 
 ```c++
 bool millerRabin(int n) {
+  if (n < 3) return n == 2;
   for (int i = 1; i <= s; ++i) {
     int a = rand() % (n - 2) + 2;
     if (quickPow(a, n - 1, n) != 1) return 0;
@@ -84,6 +87,7 @@ bool millerRabin(int n) {
 
 ```c++
 bool millerRabbin(int n) {
+  if (n < 3) return n == 2;
   int a = n - 1, b = 0;
   while (a % 2 == 0) a /= 2, ++b;
   for (int i = 1, j; i <= s; ++i) {
-- 
2.11.0