diff --git a/CompetitvePrograms/cavitymaphackerrank.cpp b/CompetitvePrograms/cavitymaphackerrank.cpp
new file mode 100644
index 00000000..33d811ca
--- /dev/null
+++ b/CompetitvePrograms/cavitymaphackerrank.cpp
@@ -0,0 +1,32 @@
+#include <bits/stdc++.h>
+using namespace std;
+int main()
+{
+    int n,**arr;
+    cin>>n;
+    arr=new int*[n];
+    for(int i=0;i<n;i++)
+    arr[i]=new int[n];
+    for(int i=0;i<n;i++)
+    {
+    	string s;
+    	cin>>s;
+    	for(int j=0;j<n;j++)
+            arr[i][j]=s[j]-48;
+	}  
+    for(int i=0;i<n;i++)
+    {
+        for(int j=0;j<n;j++)
+        {
+            if(i==0||j==0||i==n-1||j==n-1)
+            {
+                cout<<arr[i][j];
+            }
+           else if(arr[i][j]>arr[i-1][j]&&arr[i][j]>arr[i][j-1]&&arr[i][j]>arr[i+1][j]&&arr[i][j]>arr[i][j+1])
+            cout<<"X";
+            else cout<<arr[i][j];
+        }
+        cout<<"\n";
+    }
+}
+
diff --git a/CompetitvePrograms/coinChangeProblem.cpp b/CompetitvePrograms/coinChangeProblem.cpp
new file mode 100644
index 00000000..a1e7837e
--- /dev/null
+++ b/CompetitvePrograms/coinChangeProblem.cpp
@@ -0,0 +1,61 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main()
+{
+    int c,r;
+    int *coins,**arr;
+    cin>>c>>r;
+    coins=new int[r];
+    
+    arr=new int*[r+1];
+    for(int i=0;i<r+1;i++)
+    arr[i]=new int[c+2];
+    
+	for(int i=0;i<r;i++)
+    {
+        cin>>coins[i];
+        arr[i+1][0]=coins[i];
+    }
+    for(int i=1;i<c+2;i++)
+    arr[0][i]=i-1;
+    arr[0][0]=0;
+    for(int i=1;i<r+1;i++)
+    {
+        for(int j=1;j<c+2;j++)
+        {
+            if(i==1)
+            {
+                if(j==1)
+                arr[i][j]=1;
+                else if(arr[0][j]<arr[i][0])
+                arr[i][j]=0;
+                else if(arr[0][j]%arr[i][0]==0)
+                arr[i][j]=1;
+                else arr[i][j]=0;
+            }
+            else
+            {
+                if(arr[0][j]<arr[i][0])
+                arr[i][j]=arr[i-1][j];
+                else
+                {
+                    int sum=arr[i-1][j];
+                    sum+=arr[i][(arr[0][j]-arr[i][0])+1];
+                    //cout<<"arr[0][j]-arr[i][0] = "<<arr[0][j]-arr[i][0]<<" arr[i-1][j]= "<<arr[i-1][j]<<" sum = "<<sum<<"\n";
+                    arr[i][j]=sum;
+                }
+            }
+        }
+    }
+    for(int i=0;i<r+1;i++)
+    {
+    	for(int j=0;j<c+2;j++)
+    	{
+    		cout<<arr[i][j]<<" ";
+		}
+		cout<<"\n";
+	}
+    cout<<arr[r][c+1]<<"\n";
+}
diff --git a/CompetitvePrograms/leetcode3.cpp b/CompetitvePrograms/leetcode3.cpp
new file mode 100644
index 00000000..6f202c22
--- /dev/null
+++ b/CompetitvePrograms/leetcode3.cpp
@@ -0,0 +1,33 @@
+#include<iostream>
+using namespace std;
+bool canConstruct(string ransomNote, string magazine) 
+    {
+        int count=ransomNote.length(),j,i;
+        for( i=0;i<ransomNote.length();i++)
+        {
+        	cout<<count;
+            if(count==0)
+                return true;
+            for( j=0;j<magazine.length();j++)
+            {
+                if(magazine[j]==ransomNote[i])
+                {
+                    magazine[j]='*';
+                    count-=1;
+                    break;
+                }
+            }
+            cout<<"\n"<<j;
+            if(j==magazine.length())
+                return false;
+        }
+        if(count==0)
+        return true;
+        return false;
+    }
+int main()
+{
+	string r,m;
+	cin>>r>>m;
+	cout<<canConstruct(r,m);
+}
diff --git a/CompetitvePrograms/leetcode4.cpp b/CompetitvePrograms/leetcode4.cpp
new file mode 100644
index 00000000..ae3a4b99
--- /dev/null
+++ b/CompetitvePrograms/leetcode4.cpp
@@ -0,0 +1,21 @@
+#include<iostream>
+#include<math.h>
+using namespace std;
+int findComplement(int num) 
+    {
+        int count=0,sum=0;
+        while(num>0)
+        {
+            if(num%2==0)
+            sum+=pow(2,count);
+            num/=2;
+            count++;
+        }
+        return sum;
+    }
+int main()
+{
+	int n;
+	cin>>n;
+	cout<<findComplement(n);
+}
diff --git a/CompetitvePrograms/leetcode5.cpp b/CompetitvePrograms/leetcode5.cpp
new file mode 100644
index 00000000..d310526a
--- /dev/null
+++ b/CompetitvePrograms/leetcode5.cpp
@@ -0,0 +1,23 @@
+#include<iostream>
+using namespace std;
+
+    int firstUniqChar(string s) 
+    {
+        int arr[26]={0};
+        for(int i=0;i<s.length();i++)
+        {
+            arr[s[i]-97]++;
+        }
+        for(int i=0;i<s.length();i++)
+        {
+            if(arr[s[i]-97]==1)
+                return i;
+        }
+        return -1;
+    }
+int main()    
+{
+	string s;
+	cin>>s;
+	cout<<firstUniqChar(s);
+}
diff --git a/CompetitvePrograms/leetcode6.cpp b/CompetitvePrograms/leetcode6.cpp
new file mode 100644
index 00000000..1c3e6215
--- /dev/null
+++ b/CompetitvePrograms/leetcode6.cpp
@@ -0,0 +1,35 @@
+#include<iostream>
+#include<vector>
+using namespace std;
+ int majorityElement(vector<int> nums) 
+    {
+    	
+        int arr[1000]={0},i;
+		for( i=0;i<nums.size()-1;i++)
+        {
+        	for(int j=i-1;j>=0;j--)
+        	if(nums[j]=nums[i])
+        	continue;
+        	
+            for(int j=i+1;j<nums.size();j++)
+            {
+                if(nums[i]==nums[j])
+                    arr[i]++;
+            }
+            if(arr[i]+1>nums.size()/2)
+                return nums[i];
+        }
+      return nums[i];
+    }
+int main()
+{
+	vector<int> arr(0);
+	  arr.push_back(10); 
+    arr.push_back(9); 
+    arr.push_back(9);
+
+	  arr.push_back(9); 
+    arr.push_back(10);
+	cout<<majorityElement(arr);
+}
+
diff --git a/CompetitvePrograms/queenattack.cpp b/CompetitvePrograms/queenattack.cpp
new file mode 100644
index 00000000..9c786324
--- /dev/null
+++ b/CompetitvePrograms/queenattack.cpp
@@ -0,0 +1,27 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main()
+{
+	int n,o,row,col,max;
+	int **board;
+	cin>>n>>o;
+	board=new int*[n];
+	for(int i=0;i<n;i++)
+	board[i]=new int[n];
+	for(int i=0;i<n;i++)
+		for(int j=0;i<n;j++)
+			board[i][j]=0;
+    cin>>row>>col;
+    board[row-1][col-1]=2;
+   // if((row-1==0&&col-1==0)||(row-1==0&&col-1==n-1)||(row-1==n-1&&col-1==0)||(row-1==n-1&&col-1==n-1))
+    if(row-1==0||col-1==0||row-1==n-1||col-1==n-1)
+    max=(n-1)*3;
+    
+    while(o--)
+    {
+    	cin>>row>>col;
+    	board[row-1][col-1]=1;
+	}
+	
+}
diff --git a/CompetitvePrograms/testFunctions.cpp b/CompetitvePrograms/testFunctions.cpp
new file mode 100644
index 00000000..a59734c4
--- /dev/null
+++ b/CompetitvePrograms/testFunctions.cpp
@@ -0,0 +1,29 @@
+#include<iostream>
+#include<algorithm>
+#include<numeric>
+using namespace std;
+void show(int arr[],int n)
+{
+	for(int i=0;i<n;i++)
+	cout<<arr[i]<<" ";
+	cout<<"\n";
+}
+int main()
+{
+	int arr[10]={10,12,3,3,5,78,2,1,0,43};
+	int arr2[10];
+	show(arr,10);
+	sort(arr,arr+10);
+//	cout<<binary_search(arr,arr+10,33)<<" \n";
+    show(arr,10);
+    reverse(arr,arr+10);
+    show(arr,10);
+    cout<<*max_element(arr,arr+10)<<"\n";
+    cout<<*min_element(arr,arr+10)<<"\n";
+    cout<<accumulate(arr,arr+10,0)<<"\n";
+    cout<<count(arr,arr+10,3)<<"\n";
+    cout<<find(arr,arr+10,3)-arr<<"\n";
+    //copy_n(arr,10,arr2);
+    copy_n(arr, 6, arr2);
+    show(arr2,10);
+}
diff --git a/CompetitvePrograms/testtree.cpp b/CompetitvePrograms/testtree.cpp
new file mode 100644
index 00000000..3d18a1f0
--- /dev/null
+++ b/CompetitvePrograms/testtree.cpp
@@ -0,0 +1,197 @@
+#include<iostream>
+#include<stdio.h>
+#include<malloc.h>
+#include<stdlib.h>
+using namespace std;
+struct node
+{
+	struct node *leftChild;
+	int data;
+	struct node *rightChild;
+};
+struct node *root=NULL;
+//int const MAX=100;
+int MAX=100;
+struct node *sta[100];
+int top=-1,leftheight=0,rightheight=0;
+void push(struct node *ptr);
+struct node *pop();
+void preorder(struct node* ptr);
+void display(struct node *ptr);
+struct node *create();
+void inorder(struct node* ptr);
+bool c=true;
+int co=0;
+struct node *check(struct node *ptr,int count,int element)
+    {
+    	cout<<" count : "<<count<<"\n";
+    	co=count;
+        if(ptr==NULL)
+            return NULL;
+        if(ptr->data==element)
+            return ptr;
+        struct node* parent=ptr;
+        struct node* ch=check(ptr->leftChild,count+1,element);
+        if(ch!=NULL&&c==true)
+        {
+            c=false;
+            return parent;          
+        }
+        if(c)
+        {
+            parent=ptr;
+            ch=check(ptr->rightChild,count+1,element); 
+            if(ch!=NULL&&c==true)
+        	{
+            c=false;
+            return parent;          
+        	}
+        }
+        
+        return ch;
+    }
+    bool isCousins(struct node *ptr, int x, int y) 
+    {
+        int co1,co2;
+        co=0;
+        c=true;
+        struct node *n=check(ptr,0,x);
+        co1=co;
+        co=0;
+        c=true;
+        struct node *m=check(ptr,0,y);
+        co2=co;
+        if(co1==co2&&n->data!=m->data)
+            return true; 
+        else return false;
+    }
+/*int heightofleftsubtree(struct node* ptr)
+{
+	if(ptr==NULL)
+	return 0;
+	while(ptr->leftChild!=NULL)
+	{
+	  ptr=ptr->leftChild;
+	  leftheight++;	
+	}
+	if(ptr->rightChild==NULL)
+	return leftheight;
+	else heightofleftsubtree(ptr->rightChild);
+}
+int heightofrightsubtree(struct node* ptr)
+{
+	if(ptr==NULL)
+	return 0;
+	while(ptr->rightChild!=NULL)
+	{
+		ptr=ptr->rightChild;
+	    rightheight++;
+	}
+	if(ptr->leftChild==NULL)
+}*/
+void push(struct node *ptr)
+{
+	if(top==(MAX-1))
+	{
+		printf("Stack OverFlow\n");
+		return;
+	}
+	else sta[++top]=ptr;
+}
+
+struct node *pop()
+{
+	if(top==-1)
+	{
+		printf("Stack UnderFlow");
+		exit(0);
+	}
+	else return sta[top--];
+}
+int main()
+{
+	root=create();
+	printf("Preorder traversal of tree : ");
+	inorder(root);
+	cout<<"Enter the element to check : ";
+	int a;
+	cin>>a;
+	c=true;
+	struct node *ptr=check(root,0,a);
+	cout<<ptr->data<<" "<<co;
+	cout<<"\n"<<isCousins(root,4,5);
+	return 0;
+}
+
+void display(struct node *ptr)
+{
+	if(ptr==NULL)
+	return;
+	printf("%d ",ptr->data);
+	display(ptr->leftChild);
+	display(ptr->rightChild);
+}
+void preorder(struct node* ptr)
+{
+	if(ptr==NULL)
+    {
+        printf("Tree is empty!");
+        return;
+    }
+	push(ptr);
+	while(top!=-1);
+	{	
+	    ptr=pop();
+		printf("%d ",ptr->data);
+		if(ptr->rightChild!=NULL)
+		push(ptr->rightChild);
+		if(ptr->leftChild!=NULL)
+		push(ptr->leftChild);	
+	}
+}
+void inorder(struct node* ptr)
+{
+	if(ptr==NULL)
+    {
+        printf("Tree is empty!");
+        return;
+    }
+    while(1)
+    {
+    	while(ptr->leftChild!=NULL)
+    	{
+    		push(ptr);
+    		ptr=ptr->leftChild;
+		}
+		while(ptr->rightChild==NULL)
+		{
+			printf("1  test ptr->left =%u   ptr->right=%u    ptr->info=%d  \n",ptr->leftChild,ptr->rightChild,ptr->data);
+			printf("loop In %d \n",ptr->data);
+			if(top==-1)
+			return;
+			ptr=pop();
+		}
+		printf("test ptr->left =%u   ptr->right=%u    ptr->info=%d  \n",ptr->leftChild,ptr->rightChild,ptr->data);
+		printf("In %d \n",ptr->data);
+		ptr=ptr->rightChild;
+	    printf("test ptr->left =%u   ptr->right=%u    ptr->info=%d  \n",ptr->leftChild,ptr->rightChild,ptr->data);
+	}
+}
+struct node *create()
+{
+	struct node *temp=NULL;
+	int x;
+	printf("Enter the data(0 for no node) : ");
+	scanf("%d",&x);
+	if(x==0)
+	return NULL;
+	temp=(struct node*)malloc(sizeof(struct node));
+	temp->data=x;
+	printf("Enter the Left Child Of %d : \n",x);
+	temp->leftChild=create();
+
+	printf("Enter the Right Child Of %d : \n",x);
+	temp->rightChild=create();
+	
+	return temp;
+}