Merge pull request #14 from LuaanNguyen/leetcode-680

680 + 344

Author: LuaanNguyen

README.md

@@ -57,6 +57,8 @@ go clean -testcache
 |                          [167](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)                           | [Two Sum II - Input Array Is Sorted](/medium/167_two_sum_II_input_array_is_sorted)                                          |          medium           |                                         _`Two Pointers`_                                         |                       We know that the array is sorted in asc order. We can track the total sum of 2 pointers left and right and increase or decrease their indices accordingly in a while loop                        |
 |                                         [15](https://leetcode.com/problems/3sum/description/)                                         | [3Sum](/medium/15_3sum)                                                                                                     |          medium           |                                         _`Two Pointers`_                                         |                            Interate through the array, initialize 2 other pointers j = i + 1 and k = n - 1 and check the sum and adjust j and k accordingly. Make sure to check duplicates                             |
 |                 [3375](https://leetcode.com/problems/minimum-operations-to-make-array-values-equal-to-k/description)                  | [3Sum](/easy/3375_minimum_operations_to_make_array_values_equal_to_k)                                                       |          medium           |                                           _`Hashmap`_                                            |                                   There is no solution if a value that smaller than k. If a value is larger than k, we add it to our set and count the length of the set at the end                                    |
+|                                 [680](https://leetcode.com/problems/valid-palindrome-ii/description/)                                 | [Valid Palindrome II](/easy/680_valid_palindrome_II)                                                                        |           easy            |                                         _`Two Pointers`_                                         |                                  Have a helper function which has the same structure as the main function. Use 2 pointers to check the +1 or -1 element whether they are equal or not                                  |
+|                                   [344](https://leetcode.com/problems/reverse-string/description/)                                    | [Reverse String](/easy/344_reverse_string)                                                                                  |           easy            |                                         _`Two Pointers`_                                         |                                                                                                                                                                                                                        |
 
 ## Workflow 🌊
 
@@ -73,8 +75,6 @@ go clean -testcache
 - Update `README.md` with current stats
 - Automaticall commits and pushes the changes
 
-
-
 ## Statistics 📊
 
 - Easy: 5 solutions

easy/344_reverse_string/344_reverse_string.go

@@ -0,0 +1,15 @@
+package reverse_string
+
+func reverseString(s []byte)  {
+    l := 0 
+    r := len(s) - 1
+
+    for l < r {
+        temp := s[l]
+        s[l] = s[r]
+        s[r] = temp
+        
+        l++
+        r--
+    }
+}

easy/344_reverse_string/344_reverse_string_test.go

@@ -0,0 +1,34 @@
+package reverse_string
+
+import "testing"
+
+func TestReverseString(t *testing.T) {
+	tests := []struct {
+		name 	string 
+		s 	[]byte
+		expectedResult 	[]byte 
+	} {
+		{
+			name: "Test Case 1", 
+			s: []byte{'h','e','l','l','o'},
+			expectedResult: []byte{'o','l','l','e','h'}, 
+		},
+		{
+			name: "Test Case 1", 
+			s: []byte{'H','a','n','n','a','h'},
+			expectedResult: []byte{'h','a','n','n','a','H'}, 
+		},
+
+		
+	
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			reverseString(test.s)
+			if string(test.s) != string(test.expectedResult) {
+				t.Errorf("reverseString(%s) = %s; want = %s", test.s, test.s, test.expectedResult)
+			}
+		})
+	}
+}

easy/680_valid_palindrome_II/680_valid_palindrome_II.go

@@ -0,0 +1,28 @@
+package valid_palindrome_II
+
+func validPalindrome(s string) bool {
+    l := 0 
+    r := len(s) - 1
+    
+    for l <= r {
+        if s[l] != s[r] {
+           return CheckPalindrome(s, l, r - 1) || CheckPalindrome(s,l + 1, r)
+        }
+        l ++ 
+        r -- 
+    }
+
+    return true 
+}
+
+// Helper
+func CheckPalindrome(s string, i, j int) bool {
+    for i < j {
+        if s[i] != s[j] {
+            return false
+        }
+        i ++
+        j --
+    }
+    return true
+}

easy/680_valid_palindrome_II/680_valid_palindrome_II_test.go

@@ -0,0 +1,37 @@
+package valid_palindrome_II
+
+import "testing"
+
+func TestValidPalindrome(t *testing.T) {
+	tests := []struct {
+		name 	string 
+		s 	string 
+		expectedResult 	bool 
+	} {
+		{
+			name: "Test Case 1", 
+			s: "aba",
+			expectedResult: true, 
+		},
+		{
+			name: "Test Case 2", 
+			s: "abca",
+			expectedResult: true, 
+		},
+		{
+			name: "Test Case 3", 
+			s: "abc",
+			expectedResult: false, 
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := validPalindrome(test.s)
+
+			if got != test.expectedResult {
+				t.Errorf("checkPalindrome(%s) = %t; want = %t", test.s, got, test.expectedResult)
+			}
+		})
+	}
+}