diff --git a/saurabh yadav/11th may class answers/1.cpp b/saurabh yadav/11th may class answers/1.cpp
new file mode 100644
index 0000000..7ac0b17
--- /dev/null
+++ b/saurabh yadav/11th may class answers/1.cpp	
@@ -0,0 +1,46 @@
+ 
+#include <bits/stdc++.h> 
+using namespace std; 
+
+int getSingle(int arr[], int n) 
+{ 
+	int ones = 0, twos = 0 ; 
+
+	int common_bit_mask; 
+
+
+	for( int i=0; i< n; i++ ) 
+	{ 
+		twos = twos | (ones & arr[i]); 
+
+
+		
+		ones = ones ^ arr[i]; 
+
+
+	
+		common_bit_mask = ~(ones & twos); 
+
+
+		ones &= common_bit_mask; 
+
+
+		
+		twos &= common_bit_mask; 
+
+	
+	} 
+
+	return ones; 
+} 
+
+
+int main() 
+{ 
+	int arr[] = {3, 3, 2, 3}; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+	cout<<"The element with single occurrence is "<<getSingle(arr, n); 
+	return 0; 
+} 
+
+
diff --git a/saurabh yadav/11th may class answers/1.exe b/saurabh yadav/11th may class answers/1.exe
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index 0000000..a54c96c
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diff --git a/saurabh yadav/11th may class answers/2.cpp b/saurabh yadav/11th may class answers/2.cpp
new file mode 100644
index 0000000..b946589
--- /dev/null
+++ b/saurabh yadav/11th may class answers/2.cpp	
@@ -0,0 +1,28 @@
+
+#include <bits/stdc++.h> 
+using namespace std; 
+
+ 
+int minXOR(int arr[], int n) 
+{ 
+	int min_xor = INT_MAX; 
+
+	
+	for (int i = 0; i < n; i++) 
+		for (int j = i + 1; j < n; j++) 
+
+		
+			min_xor = min(min_xor, arr[i] ^ arr[j]); 
+
+	return min_xor; 
+} 
+
+
+int main() 
+{ 
+	int arr[] = { 9, 5, 3 }; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+	cout << minXOR(arr, n) << endl; 
+	return 0; 
+} 
+
diff --git a/saurabh yadav/11th may class answers/2.exe b/saurabh yadav/11th may class answers/2.exe
new file mode 100644
index 0000000..eba266f
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diff --git a/saurabh yadav/11th may class answers/3.cpp b/saurabh yadav/11th may class answers/3.cpp
new file mode 100644
index 0000000..f6609a8
--- /dev/null
+++ b/saurabh yadav/11th may class answers/3.cpp	
@@ -0,0 +1,46 @@
+
+#include <bits/stdc++.h> 
+using namespace std; 
+
+
+int solve(int low, int high, int T) 
+{ 
+	while (low <= high) { 
+		int mid = (low + high) / 2; 
+
+		
+		if ((mid * (mid + 1)) == T) 
+			return mid; 
+
+		
+		if (mid > 0 && (mid * (mid + 1)) > T && 
+						(mid * (mid - 1)) <= T) 
+			return mid - 1; 
+
+	
+		if ((mid * (mid + 1)) > T) 
+			high = mid - 1; 
+
+	
+		else
+			low = mid + 1; 
+	} 
+	return -1; 
+} 
+
+int main() 
+{ 
+	int T = 15; 
+
+	
+	int ans = solve(1, T, 2 * T); 
+
+
+	if (ans != -1) 
+		ans--; 
+
+	cout << "Number of stair steps = "
+		<< ans << endl; 
+	return 0; 
+} 
+
diff --git a/saurabh yadav/11th may class answers/3.exe b/saurabh yadav/11th may class answers/3.exe
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index 0000000..d2df6d8
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diff --git a/saurabh yadav/11th may class answers/4.cpp b/saurabh yadav/11th may class answers/4.cpp
new file mode 100644
index 0000000..e984e02
--- /dev/null
+++ b/saurabh yadav/11th may class answers/4.cpp	
@@ -0,0 +1,23 @@
+ 
+
+#include <iostream> 
+using namespace std; 
+
+
+int numberOfPaths(int m, int n) 
+{ 
+	
+	if (m == 1 || n == 1) 
+		return 1; 
+
+	
+	return numberOfPaths(m - 1, n) + numberOfPaths(m, n - 1); 
+	
+} 
+
+int main() 
+{ 
+	cout << numberOfPaths(3, 3); 
+	return 0; 
+} 
+
diff --git a/saurabh yadav/11th may class answers/4.exe b/saurabh yadav/11th may class answers/4.exe
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index 0000000..8c460da
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diff --git a/saurabh yadav/11th may class answers/5.cpp b/saurabh yadav/11th may class answers/5.cpp
new file mode 100644
index 0000000..a482f1e
--- /dev/null
+++ b/saurabh yadav/11th may class answers/5.cpp	
@@ -0,0 +1,28 @@
+
+#include<bits/stdc++.h> 
+using namespace std; 
+
+
+int floorSqrt(int x) 
+{ 
+	
+	if (x == 0 || x == 1) 
+	return x; 
+
+
+	int i = 1, result = 1; 
+	while (result <= x) 
+	{ 
+	i++; 
+	result = i * i; 
+	} 
+	return i - 1; 
+} 
+ 
+int main() 
+{ 
+	int x = 11; 
+	cout << floorSqrt(x) << endl; 
+	return 0; 
+} 
+
diff --git a/saurabh yadav/11th may class answers/5.exe b/saurabh yadav/11th may class answers/5.exe
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index 0000000..d7c6b21
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diff --git a/saurabh yadav/12th may class answers/1.cpp b/saurabh yadav/12th may class answers/1.cpp
new file mode 100644
index 0000000..005ebf1
--- /dev/null
+++ b/saurabh yadav/12th may class answers/1.cpp	
@@ -0,0 +1,35 @@
+
+#include<bits/stdc++.h> 
+
+using namespace std; 
+
+int recSearch(int arr[], int l, 
+			int r, int x) 
+{ 
+	if (r < l) 
+		return -1; 
+	if (arr[l] == x) 
+		return l; 
+	if (arr[r] == x) 
+		return r; 
+	return recSearch(arr, l + 1, 
+						r - 1, x); 
+} 
+
+int main() 
+{ 
+	int arr[] = {12, 34, 54, 2, 3}, i; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+	int x = 3; 
+	int index = recSearch(arr, 0, n - 1, x); 
+	if (index != -1) 
+	cout << "Element " << x 
+		<< " is present at index "
+		<< index; 
+	else
+		cout << "Element" << x 
+			<< " is not present" ; 
+	return 0; 
+} 
+
+
diff --git a/saurabh yadav/12th may class answers/1.exe b/saurabh yadav/12th may class answers/1.exe
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index 0000000..43d2c9f
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diff --git a/saurabh yadav/12th may class answers/2.cpp b/saurabh yadav/12th may class answers/2.cpp
new file mode 100644
index 0000000..27181ad
--- /dev/null
+++ b/saurabh yadav/12th may class answers/2.cpp	
@@ -0,0 +1,37 @@
+#include<iostream> 
+using namespace std; 
+
+int removeDuplicates(int arr[], int n) 
+{ 
+	if (n==0 || n==1) 
+		return n; 
+
+	int temp[n]; 
+
+	int j = 0; 
+	for (int i=0; i<n-1; i++) 
+
+		if (arr[i] != arr[i+1]) 
+			temp[j++] = arr[i]; 
+
+	temp[j++] = arr[n-1]; 
+
+	for (int i=0; i<j; i++) 
+		arr[i] = temp[i]; 
+
+	return j; 
+} 
+
+int main() 
+{ 
+	int arr[] = {1, 2, 2, 3, 4, 4, 4, 5, 5}; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+
+	n = removeDuplicates(arr, n); 
+
+	for (int i=0; i<n; i++) 
+	cout << arr[i] << " "; 
+
+	return 0; 
+} 
+
diff --git a/saurabh yadav/12th may class answers/2.exe b/saurabh yadav/12th may class answers/2.exe
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index 0000000..478e4fb
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diff --git a/saurabh yadav/12th may class answers/3.cpp b/saurabh yadav/12th may class answers/3.cpp
new file mode 100644
index 0000000..6c4b272
--- /dev/null
+++ b/saurabh yadav/12th may class answers/3.cpp	
@@ -0,0 +1,27 @@
+
+#include <iostream> 
+using namespace std; 
+
+void decToBinary(int n) 
+{ 
+	int binaryNum[32]; 
+
+	int i = 0; 
+	while (n > 0) { 
+
+		binaryNum[i] = n % 2; 
+		n = n / 2; 
+		i++; 
+	} 
+
+	for (int j = i - 1; j >= 0; j--) 
+		cout << binaryNum[j]; 
+} 
+
+int main() 
+{ 
+	int n = 17; 
+	decToBinary(n); 
+	return 0; 
+} 
+
diff --git a/saurabh yadav/12th may class answers/3.exe b/saurabh yadav/12th may class answers/3.exe
new file mode 100644
index 0000000..bd55f16
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diff --git a/saurabh yadav/12th may class answers/4.cpp b/saurabh yadav/12th may class answers/4.cpp
new file mode 100644
index 0000000..4da36fb
--- /dev/null
+++ b/saurabh yadav/12th may class answers/4.cpp	
@@ -0,0 +1,27 @@
+#include <stdio.h> 
+#include <string.h> 
+
+void isPalindrome(char str[]) 
+{ 
+	int l = 0; 
+	int h = strlen(str) - 1; 
+
+	while (h > l) 
+	{ 
+		if (str[l++] != str[h--]) 
+		{ 
+			printf("%s is Not Palindrome", str); 
+			return; 
+		} 
+	} 
+	printf("%s is palindrome", str); 
+} 
+
+int main() 
+{ 
+	isPalindrome("yadav"); 
+	isPalindrome("\nji"); 
+	isPalindrome("\nrocks"); 
+	return 0; 
+}
+
diff --git a/saurabh yadav/12th may class answers/4.exe b/saurabh yadav/12th may class answers/4.exe
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index 0000000..8fbbe9f
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diff --git a/saurabh yadav/12th may class answers/5.cpp b/saurabh yadav/12th may class answers/5.cpp
new file mode 100644
index 0000000..a9b0400
--- /dev/null
+++ b/saurabh yadav/12th may class answers/5.cpp	
@@ -0,0 +1,18 @@
+
+#include <stdio.h> 
+int main() 
+{ 
+	char s1[] = "nahi aata tha fork vgerh to late ho gaya uploding... consider kr lena isse bhi!!", s2[100], i; 
+
+	printf("string s1 : %s\n", s1); 
+
+	for (i = 0; s1[i] != '\0'; ++i) { 
+		s2[i] = s1[i]; 
+	} 
+
+	s2[i] = '\0'; 
+
+	printf("String s2 : %s", s2); 
+
+	return 0; 
+} 
diff --git a/saurabh yadav/12th may class answers/5.exe b/saurabh yadav/12th may class answers/5.exe
new file mode 100644
index 0000000..916ba14
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diff --git a/saurabh yadav/13th may class answers/1.c b/saurabh yadav/13th may class answers/1.c
new file mode 100644
index 0000000..337f9b6
--- /dev/null
+++ b/saurabh yadav/13th may class answers/1.c	
@@ -0,0 +1,43 @@
+#include<stdio.h>
+
+#define m 20
+
+main(){
+
+int a[m][m],i,j=0,r,max[10],c;
+
+printf("Enter the number of rows");
+
+scanf("%d",&r);
+
+printf("Enter the number of column");
+
+scanf("%d",&c);
+
+printf("Enter the elements");
+
+for(i=0;i<r;i++)
+
+for(j=0;j<c;j++)
+
+scanf("%d",&a[i][j]);
+
+for(i=0;i<r;i++)
+
+{
+
+max[i]=a[i][j];
+
+for(j=0;j<c;j++)
+
+if(a[i][j]>max[i])
+
+max[i]=a[i][j];
+
+}
+
+for(i=0;i<r;i++)
+
+printf("\nMaximum element from %d row is:%d",i,max[i]);
+
+}
diff --git a/saurabh yadav/13th may class answers/1.exe b/saurabh yadav/13th may class answers/1.exe
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diff --git a/saurabh yadav/13th may class answers/2.c b/saurabh yadav/13th may class answers/2.c
new file mode 100644
index 0000000..b028d4d
--- /dev/null
+++ b/saurabh yadav/13th may class answers/2.c	
@@ -0,0 +1,55 @@
+#include <stdio.h>
+ 
+int main()
+{
+  int m, n, p, q, c, d, k, sum = 0;
+  int first[10][10], second[10][10], multiply[10][10];
+ 
+  printf("Enter the number of rows and columns of first matrix\n");
+  scanf("%d%d", &m, &n);
+  printf("Enter the elements of first matrix\n");
+ 
+  for (  c = 0 ; c < m ; c++ )
+    for ( d = 0 ; d < n ; d++ )
+      scanf("%d", &first[c][d]);
+ 
+  printf("Enter the number of rows and columns of second matrix\n");
+  scanf("%d%d", &p, &q);
+ 
+  if ( n != p )
+    printf("Matrices with entered orders can't be multiplied with each other.\n");
+  else
+  {
+    printf("Enter the elements of second matrix\n");
+ 
+    for ( c = 0 ; c < p ; c++ )
+      for ( d = 0 ; d < q ; d++ )
+        scanf("%d", &second[c][d]);
+ 
+    for ( c = 0 ; c < m ; c++ )
+    {
+      for ( d = 0 ; d < q ; d++ )
+      {
+        for ( k = 0 ; k < p ; k++ )
+        {
+          sum = sum + first[c][k]*second[k][d];
+        }
+ 
+        multiply[c][d] = sum;
+        sum = 0;
+      }
+    }
+ 
+    printf("Product of entered matrices:-\n");
+ 
+    for ( c = 0 ; c < m ; c++ )
+    {
+      for ( d = 0 ; d < q ; d++ )
+        printf("%d\t", multiply[c][d]);
+ 
+      printf("\n");
+    }
+  }
+ 
+  return 0;
+}
diff --git a/saurabh yadav/13th may class answers/2.exe b/saurabh yadav/13th may class answers/2.exe
new file mode 100644
index 0000000..4bbee51
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diff --git a/saurabh yadav/13th may class answers/3.c b/saurabh yadav/13th may class answers/3.c
new file mode 100644
index 0000000..68afd88
--- /dev/null
+++ b/saurabh yadav/13th may class answers/3.c	
@@ -0,0 +1,24 @@
+#include <stdio.h>
+int main() {
+  int a, b, x, y, t, gcd, lcm;
+
+  printf("Enter two integers\n");
+  scanf("%d%d", &x, &y);
+
+  a = x;
+  b = y;
+
+  while (b != 0) {
+    t = b;
+    b = a % b;
+    a = t;
+  }
+
+  gcd = a;
+  lcm = (x*y)/gcd;
+
+  printf("Greatest common divisor of %d and %d = %d\n", x, y, gcd);
+  printf("Least common multiple of %d and %d = %d\n", x, y, lcm);
+
+  return 0;
+}
diff --git a/saurabh yadav/13th may class answers/3.exe b/saurabh yadav/13th may class answers/3.exe
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index 0000000..bdc7811
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diff --git a/saurabh yadav/13th may class answers/4.c b/saurabh yadav/13th may class answers/4.c
new file mode 100644
index 0000000..3abc1a0
--- /dev/null
+++ b/saurabh yadav/13th may class answers/4.c	
@@ -0,0 +1,16 @@
+#include <stdio.h>
+int main() {
+    int n, rev = 0, remainder;
+    printf("Enter an integer: ");
+    scanf("%d", &n);
+    while (n != 0) {
+        remainder = n % 10;
+        rev = rev * 10 + remainder;
+        n /= 10;
+	}
+        
+   
+	 printf("\nReversed number = %d", rev);
+    
+	
+}
diff --git a/saurabh yadav/13th may class answers/4.exe b/saurabh yadav/13th may class answers/4.exe
new file mode 100644
index 0000000..57f1ed2
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diff --git a/saurabh yadav/13th may class answers/5.c b/saurabh yadav/13th may class answers/5.c
new file mode 100644
index 0000000..b3f503e
--- /dev/null
+++ b/saurabh yadav/13th may class answers/5.c	
@@ -0,0 +1,39 @@
+
+ 
+    #include <stdio.h>
+    void main()
+    {
+ 
+        int i, j, a, n, number[30];
+        printf("Enter the value of N \n");
+        scanf("%d", &n);
+ 
+        printf("Enter the numbers \n");
+        for (i = 0; i < n; ++i)
+            scanf("%d", &number[i]);
+ 
+        for (i = 0; i < n; ++i) 
+        {
+ 
+            for (j = i + 1; j < n; ++j)
+            {
+ 
+                if (number[i] > number[j]) 
+                {
+ 
+                    a =  number[i];
+                    number[i] = number[j];
+                    number[j] = a;
+ 
+                }
+ 
+            }
+ 
+        }
+ 
+        printf("The numbers arranged in ascending order are given below \n");
+        for (i = 0; i < n; ++i)
+            printf("%d\n", number[i]);
+            
+        }
+ 
diff --git a/saurabh yadav/13th may class answers/5.exe b/saurabh yadav/13th may class answers/5.exe
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