From f9a2d4d447a7269ce25d1e588b76a5ab0e96ddf7 Mon Sep 17 00:00:00 2001
From: Can Huynh <58443871+canhuynh1998@users.noreply.github.com>
Date: Mon, 13 Sep 2021 06:41:46 -0700
Subject: [PATCH] chore(Go): added Palindrome and Single Number (#454)

Co-authored-by: Ming Tsai <37890026+ming-tsai@users.noreply.github.com>
---
 algorithms/Go/README.md                       |  6 ++-
 algorithms/Go/arrays/single-number.go         | 52 +++++++++++++++++++
 .../Go/strings/palindrome-permutation.go      | 40 ++++++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 algorithms/Go/arrays/single-number.go
 create mode 100644 algorithms/Go/strings/palindrome-permutation.go

diff --git a/algorithms/Go/README.md b/algorithms/Go/README.md
index 62968bd4..3da495d7 100644
--- a/algorithms/Go/README.md
+++ b/algorithms/Go/README.md
@@ -5,6 +5,7 @@
 2. [Two Sum](arrays/two-sum.go)
 3. [Majority Element](arrays/majority_element.go)
 4. [Contains Duplicate](arrays/contains_duplicate.go)
+5. [Single Number](arrays/single-number.go)
 
 ## Scheduling
 1. [Interval Scheduling](scheduling/interval-scheduling.go)
@@ -20,4 +21,7 @@
 3. [Quicksort](sorting/quicksort.go)
 
 ## Recursion
-1. [Fibonacci](recursion/fibonacci.go)
\ No newline at end of file
+1. [Fibonacci](recursion/fibonacci.go)
+
+## String
+1. [Palindrome Permutation](strings/palindrome-permutation.go)
\ No newline at end of file
diff --git a/algorithms/Go/arrays/single-number.go b/algorithms/Go/arrays/single-number.go
new file mode 100644
index 00000000..b540b826
--- /dev/null
+++ b/algorithms/Go/arrays/single-number.go
@@ -0,0 +1,52 @@
+package arrays
+
+import "fmt"
+/*
+Given a non-empty array of int, every element appears twice except for 1.
+Find that element.
+*/
+
+/*
+Hash table approach
+	Time: O(n)
+	Space: O(n)
+*/
+
+func singleNumberWithHashTable(nums [] int) int{
+	counts := make(map[int] int)
+    for _, num := range nums{
+        counts[num]++
+    }
+    
+    for key, value := range counts{
+        if value == 1{
+            return key
+        }
+    }
+    return -1
+}
+
+/*
+Bit-manipulation approach
+	Time: O(n)
+	Space: O(1)
+*/
+func singleNumberWithConstantSpace(nums [] int) int{
+	result := 0
+	for _, num := range nums{
+		result ^= num
+	}
+	return result
+}
+
+func runSingleNumber(){
+	input1 := []int{2,2,1}
+	input2 := []int{4,1,2,1,2}
+
+	fmt.Printf("The Single Number for input 1 is %d\n",singleNumberWithConstantSpace(input1))
+	fmt.Printf("The Single Number for input 2 is %d\n",singleNumberWithConstantSpace(input2))
+
+	fmt.Printf("The Single Number for input 1 is %d\n",singleNumberWithHashTable(input1))
+	fmt.Printf("The Single Number for input 2 is %d\n",singleNumberWithHashTable(input2))
+
+}
\ No newline at end of file
diff --git a/algorithms/Go/strings/palindrome-permutation.go b/algorithms/Go/strings/palindrome-permutation.go
new file mode 100644
index 00000000..779f8660
--- /dev/null
+++ b/algorithms/Go/strings/palindrome-permutation.go
@@ -0,0 +1,40 @@
+package strings
+
+import( 
+    "strings"  
+	"fmt"
+)
+
+/*
+Given a string s, return true if we can have a palindrome from the permutation of the input
+
+	Time: O(n)
+	Space: O(n)
+*/
+func canPermutePalindrome(s string) bool {
+    a := strings.Split(s,"")
+    dictionary := make(map[string] int)
+    for _, char := range(a){
+        dictionary[char]++
+    }
+    
+    odd := 0
+    for _, value := range dictionary{
+        if value % 2 != 0{
+            odd++
+        }
+    }
+    return odd <= 1
+}
+
+
+//You are welcome to play around with the test cases
+func runPermutationCheck(){
+	input1 := "carerac"
+
+	fmt.Printf("%t for input %s \n", canPermutePalindrome(input1), input1)	//should print true
+
+	input2 := "code"
+	fmt.Printf("%t for input %s \n", canPermutePalindrome(input2), input2)	//should print false
+
+}
\ No newline at end of file