maths

XOR sum of pairwisebit AND.cpp

@@ -0,0 +1,14 @@
+int getXORSum(vector<int>& arr1, vector<int>& arr2) {
+        int n,m,i,j;
+        n=arr1.size();
+        m=arr2.size();
+        int ans1,ans2;
+        ans1=arr1[0];
+        ans2=arr2[0];
+        for(i=1;i<n;i++)
+            ans1=ans1^arr1[i];
+        for(i=1;i<m;i++)
+            ans2=ans2^arr2[i];
+        return ans1&ans2;
+
+    }

express number as a sum of consecutive numbers.cpp

@@ -0,0 +1,38 @@
+// C++ program to print a consecutive sequence
+// to express N if possible.
+#include <bits/stdc++.h>
+using namespace std;
+
+// Print consecutive numbers from
+// last to first
+void printConsecutive(int last, int first)
+{
+	cout << first++;
+	for (int x = first; x<= last; x++)
+		cout << " + " << x;
+}
+
+void findConsecutive(int N)
+{
+	for (int last=1; last<N; last++)
+	{
+		for (int first=0; first<last; first++)
+		{
+			if (2*N == (last-first)*(last+first+1))
+			{
+				cout << N << " = ";
+				printConsecutive(last, first+1);
+				return;
+			}
+		}
+	}
+	cout << "-1";
+}
+
+// Driver code
+int main()
+{
+	int n = 12;
+	findConsecutive(n);
+	return 0;
+}

numbers which can be constructed by two numbers.cpp

@@ -0,0 +1,34 @@
+ int getCount(int x, int y, int n) {
+       bool arr[n+1];
+       memset(arr,false,sizeof(arr));
+       int result=0;
+       if(x<=n)
+       {
+       arr[x]=true;
+      // result++;
+       }
+       if(y<=n)
+       {
+           arr[y]=true;
+        //   result++;
+       }
+       for(int i=min(x,y);i<=n;i++)
+       {
+           if(arr[i])
+           {
+               if(i+x<=n)
+               {
+                   arr[i+x]=true;
+                  // result++;
+               }
+               if(i+y<=n)
+               {
+                   arr[i+y]=true;
+                   //result++;
+               }
+               result++;
+           }
+       }
+       return result;
+
+    }