Added some code

leetcode/problems/c/reverse-integer.c

@@ -0,0 +1,16 @@
+// by @codeAbinash
+// Time : O(1)
+// Space : O(1)
+
+#include "limits.h"
+
+int reverse(int x) {
+   long reversed = 0;
+   while (x) {
+      reversed = reversed * 10 + x % 10;
+      x /= 10;
+   }
+   if (reversed > INT_MAX || reversed < INT_MIN)
+      return 0;
+   return x < 0 ? -reversed : reversed;
+}

leetcode/problems/c/reverse-vowels-of-a-string.c

@@ -1,25 +1,26 @@
 // by @codeAbinash
-// Time Complexity : O(n)
-// Space Complexity : O(1)
+// Time : O(n)
+// Space : O(1)
 
-int isVowel(char c) {
-    return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u' ||
-           c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U';
+void inline swap(char* a, char* b) {
+   char tmp = *a;
+   *a = *b;
+   *b = tmp;
 }
 
-char* reverseVowels(char* s) {
-    int start = 0, end = strlen(s) - 1;
-    char tmp;
-
-    while (start < end && (s[start] || s[end])) {
-        if (!isVowel(s[start])) start++;
-        if (!isVowel(s[end])) end--;
+bool inline isVowel(char c) {
+   return strchr("aeiouAEIOU", c) != NULL;
+}
 
-        if (isVowel(s[start]) && isVowel(s[end])) {
-            tmp = s[start];
-            s[start++] = s[end];
-            s[end--] = tmp;
-        }
-    }
-    return s;
+char* reverseVowels(char* s) {
+   char* start, * end, tmp;
+   start = s;
+   end = s + strlen(s) - 1;
+   while (start < end) {
+      while (start < end && !isVowel(*start)) start++;
+      while (start < end && !isVowel(*end)) end--;
+      swap(start, end);
+      start++, end--;
+   }
+   return s;
 }

leetcode/problems/cpp/reverse-integer.cpp

@@ -0,0 +1,23 @@
+// by @codeAbinash
+// Time : O(1)
+// Space : O(1)
+
+#include "climits"
+#include "bits/std_abs.h"
+
+using namespace std;
+class Solution {
+public:
+   int reverse(int x) {
+      bool isNegative = x < 0;
+      long int reversed = 0;
+      x = abs(x);
+      while (x) {
+         reversed = reversed * 10 + x % 10;
+         x /= 10;
+      }
+      if (reversed > INT_MAX || reversed < INT_MIN)
+         return 0;
+      return isNegative ? -reversed : reversed;
+   }
+};

leetcode/problems/cpp/reverse-vowels-of-a-string.cpp

@@ -0,0 +1,24 @@
+// by @codeAbinash
+// Time : O(n)
+// Space : O(1)
+
+#include "vector"
+#include "string"
+#include "string.h"
+using namespace std;
+
+bool inline isVowel(char c) {
+   return strchr("aeiouAEIOU", c) != NULL;
+}
+class Solution {
+public:
+   string reverseVowels(string s) {
+      int i = 0, j = s.size() - 1;
+      while (i < j) {
+         while (i < j && !isVowel(s[i])) i++;
+         while (i < j && !isVowel(s[j])) j--;
+         swap(s[i++], s[j--]);
+      }
+      return s;
+   }
+};

leetcode/problems/cpp/valid-anagram.cpp

@@ -0,0 +1,27 @@
+// by @codeAbinash
+// Time : O(n)
+// Space : O(1)
+
+#include "string"
+#include "vector"
+using namespace std;
+
+class Solution {
+public:
+   bool isAnagram(string s, string t) {
+      int s_len = s.length();
+      int t_len = t.length();
+
+      if (s_len != t_len) return false;
+
+      int hash[26] = { 0 };
+      for (int i = 0; i < s_len; i++) {
+         hash[s[i] - 'a']++;
+         hash[t[i] - 'a']--;
+      }
+      // Check if all the elements in the hash are 0
+      for (int i = 0; i < 26; i++)
+         if (hash[i] != 0) return false;
+      return true;
+   }
+};

leetcode/problems/cpp/word-pattern.cpp

@@ -0,0 +1,22 @@
+// by @codeAbinash
+
+#include "iostream"
+#include "map"
+
+using namespace std;
+
+class Solution {
+public:
+    bool wordPattern(string pattern, string s) {
+        map<char, int> p2i;
+        map<string, int> w2i;
+        istringstream in(s);
+        int i = 0, n = pattern.size();
+        for (string word; in >> word; ++i) {
+            if (i == n || p2i[pattern[i]] != w2i[word])
+                return false;
+            p2i[pattern[i]] = w2i[word] = i + 1;
+        }
+        return i == n;
+    }
+};