Kalke questions

Author: ChSatyaSavith

125. Valid Palindrome.cpp

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    bool isPalindrome(string s)
+    {
+        string toreturn = "";
+
+        for(auto x: s)
+        {
+            if(iswalnum(x))
+            {
+                toreturn+=tolower(x);
+            }
+        }
+        string x = toreturn;
+        reverse(toreturn.begin(),toreturn.end());
+        return x==toreturn;
+    }
+};

137. Single Number II.cpp

@@ -0,0 +1,42 @@
+class Solution {
+public:
+    int singleNumber(vector<int>& nums)
+    {
+        vector<int> result;
+        for(int i = 0;i<32;i++)
+        {
+            int one = 0;
+            int zero = 0;
+            for(auto x: nums)
+            {
+                if((x>>i)&1)
+                {
+                    one+=1;
+                }
+                else
+                {
+                    zero+=1;
+                }
+            }
+
+            one %= 3;
+            zero %= 3;
+
+            if(one==0)
+            {
+                result.push_back(0);
+            }
+            if(zero==0)
+            {
+                result.push_back(1);
+            }
+        }
+        long  ans = 0;
+        for(int i = 0;i<32;i++)
+        {
+            ans += result[i]*long(pow(2,i));
+        }
+
+        return ans;
+    }
+};

66. Plus One.cpp

@@ -0,0 +1,42 @@
+class Solution {
+public:
+    vector<int> plusOne(vector<int>& digits)
+    {
+        reverse(digits.begin(),digits.end());
+        int carry = 0;
+        bool flag = false;
+        digits[0] += 1;
+        if(digits[0]>=10)
+        {
+            digits[0] %= 10;
+            carry = 1;
+            flag = true;
+        }
+        else
+        {
+            carry = 0;
+        }
+        for(int i = 1;i<digits.size();i++)
+        {
+            flag = false;
+            digits[i] += carry;
+
+            if(digits[i]>=10)
+            {
+                digits[i] %= 10;
+                carry = 1;
+                flag = true;
+            }
+            else
+            {
+                carry = 0;
+            }
+        }
+        if(flag)
+        {
+            digits.push_back(1);
+        }
+        reverse(digits.begin(),digits.end());
+        return digits;  
+    }
+};