Merge pull request codewithdev#63 from ShreyashRoyzada/master

Added 5 LeetCode Questions.

Author: codewithdev

ONLINE JUDGE/LeetCode/#15-3Sum.cpp

@@ -0,0 +1,49 @@
+class Solution {
+  public:
+    vector<vector<int>> threeSum(vector<int>& A) {
+        if(A.size()<3)
+        {
+            vector<vector<int>> emp;
+            return emp;
+        }
+      set<vector<int>> ans;
+      sort(A.begin(),A.end());
+      for(int i=0;i<A.size()-2;i++)
+      {
+        if(i==0||A[i]>A[i-1])
+        {
+        int left=i+1,right=A.size()-1;
+        
+        while(left<right)
+        {
+          if(A[left]+A[right]>(-A[i]))
+          {
+              right--;
+          }
+          else if(A[left]+A[right]<(-A[i]))
+          {
+              left++;
+          }
+          
+          if((right!=left)&&(A[left]+A[right]==(-A[i])))
+          {
+          vector<int> temp;
+          temp.push_back(A[i]);
+          temp.push_back(A[left]);
+          temp.push_back(A[right]);
+          ans.insert(temp);
+          left++;
+          right--;
+          }
+        }
+        
+        }
+      }
+      vector<vector<int>> ans1;
+      for(auto itr=ans.begin();itr!=ans.end();itr++)
+      {
+        ans1.push_back(*(itr));
+      }
+      return ans1;
+    }
+};

ONLINE JUDGE/LeetCode/#409 Longest Palindrome.cpp

@@ -0,0 +1,35 @@
+class Solution {
+  public:
+    int longestPalindrome(string s) {
+     map<char,int> check;
+     int ans=0;
+     for(int i=0;i<s.size();i++)
+     {
+       check[s[i]]++;
+     }
+     vector<int> temp;
+     for(auto &x : check)
+     {
+       int val = x.second;
+      
+       if(val%2==0)
+       {
+         ans=ans+val;
+       }
+       else
+       {
+         temp.push_back(val);
+       }
+     }
+     if(temp.size()!=0)
+     {
+         ans = ans+*max_element(temp.begin(),temp.end());
+         temp.erase(max_element(temp.begin(),temp.end()));
+         for(int i=0;i<temp.size();i++)
+         {
+             ans = ans + temp[i] - 1;
+         }
+     }
+     return ans;
+     }
+};

ONLINE JUDGE/LeetCode/#48-Rotate Image.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    void rotate(vector<vector<int>>& matrix) {
+        int n=matrix.size()/2,i=0,sz=matrix.size()-1;
+      for(int i=0;i<n;i++)
+      {
+        for(int j=i;j<sz-i;j++)
+        {
+          int temp1 = matrix[i][j];
+          int temp2 = matrix[j][sz-i];
+          int temp3 = matrix[sz-i][sz-j];
+          int temp4 = matrix[sz-j][i];
+          matrix[i][j] = temp4;
+          matrix[j][sz-i] = temp1;
+          matrix[sz-i][sz-j] = temp2;
+          matrix[sz-j][i] = temp3;
+        }
+      }
+    
+    }
+};

ONLINE JUDGE/LeetCode/#54 Spiral Matrix.cpp

@@ -0,0 +1,46 @@
+
+class Solution {
+  public:
+    vector<int> spiralOrder(vector<vector<int>>& matrix) {
+      vector<int> ans;
+      if(matrix.size()==0)
+      {
+          return ans;
+      }
+      int top = 0 , right = matrix[0].size()-1, bottom = matrix.size()-1, left = 0;
+      while(top<=bottom&&left<=right)
+      {
+        //top layer
+        for(int i=left;i<=right;i++)
+        {
+          ans.push_back(matrix[top][i]);
+        }
+        top++;
+        
+        //right layer
+        for(int i=top;i<=bottom;i++)
+        {
+          ans.push_back(matrix[i][right]);
+        }
+        right--;
+        if(top>bottom||left>right)
+        {
+            break;
+        }
+        //bottom layer
+        for(int i=right;i>=left;i--)
+        {
+          ans.push_back(matrix[bottom][i]);
+        }
+        bottom--;
+        
+        //left layer
+        for(int i=bottom;i>=top;i--)
+        {
+          ans.push_back(matrix[i][left]);
+        }
+        left++;
+      }
+    return ans;
+    }
+};

ONLINE JUDGE/LeetCode/#9-Palindrome Number.cpp

@@ -0,0 +1,26 @@
+class Solution {
+public:
+    
+    bool isPalindrome(int x) {
+        if(x==0)
+            return true;
+        if(x<0)
+        return false;
+      int size = log10(x)+1;
+      for(int i=0;i<size/2;i++)
+      {
+        int a=pow(10,size-1-(i*2)),b=10;
+        if(x/a!=x%b)
+        {
+          cout<<x<<" ";
+          return false;
+        }
+        else
+        {
+          x=x%a;
+          x=x/b;
+        }
+      }
+      return true;
+    }
+};