Included some more DSA problems (#339)

* Create Even Odds.cpp

* Rename Even Odds.cpp to EvenOdds.cpp

* Create EvenArray.cpp

* Create RequiredRemainder.cpp

* Create Modular Exponentiation.cpp

* Rename Modular Exponentiation.cpp to ModularExponentiation.cpp

* Create ArrayStabilization.cpp

Author: admirerr

Maths/ArrayStabilization.cpp

@@ -0,0 +1,24 @@
+#include<iostream>
+#include<string>
+#include<algorithm>
+#include<stack>
+#include<cmath>
+using namespace std;
+ 
+ 
+ 
+int main()
+ 
+{
+ 
+
+long long n;
+cin>>n;
+long long arr[n];
+for(int i=0;i<n;i++){
+    cin>>arr[i];
+}
+sort(arr,arr+n);
+cout<<min(arr[n-2]-arr[0],arr[n-1]-arr[1]);
+return 0;
+}

Maths/EvenArray.cpp

@@ -0,0 +1,22 @@
+#include <algorithm>
+#include <iostream>
+#include <vector>
+#include<set>
+ 
+using namespace std;
+ 
+int main() {
+ 
+int t;
+cin>>t;
+while(t--){
+	string s;
+	cin>>s;
+	cout<<s[0];
+	for(int i=1;i<s.length()-1;i+=2){
+		cout<<s[i];
+	}
+	cout<<s[s.length()-1]<<endl;
+}
+return 0;
+}

Maths/EvenOdds.cpp

@@ -0,0 +1,25 @@
+#include<iostream>
+#include<string>
+#include<algorithm>
+#include<stack>
+#include<cmath>
+#include<vector>
+using namespace std;
+ 
+ 
+ 
+int main()
+ 
+{
+ 
+ 
+long long n,k;
+cin>>n>>k;
+if(k<=(n+1)/2){
+    cout<<2*k-1;
+}
+else{
+    cout<<(k-(n+1)/2)*2;
+}
+return 0;
+}

Maths/ModularExponentiation.cpp

@@ -0,0 +1,31 @@
+#include<iostream>
+#include<string>
+#include<algorithm>
+#include<stack>
+#include<cmath>
+#include<vector>
+#include<math.h>
+using namespace std;
+ 
+ 
+ 
+int main()
+ 
+{
+ 
+ 
+    #ifndef ONLINE_JUDGE
+ 
+freopen("input.txt","r",stdin);
+ 
+ 
+freopen("output.txt","w",stdout);
+ 
+#endif
+ 
+int n,m;
+cin>>n>>m;
+int r=pow(2,n);
+cout<<m%r;
+return 0;
+}

Maths/RequiredRemainder.cpp

@@ -0,0 +1,25 @@
+#include<iostream>
+#include<string>
+#include<algorithm>
+using namespace std;
+ 
+ 
+ 
+int main()
+ 
+{
+ 
+int t;
+cin>>t;
+int x,y,n,k;
+for(int i=0;i<t;i++){
+    cin>>x>>y>>n;
+    if((n-n%x+y)<=n){
+        cout<<n-n%x+y<<endl;
+    }
+    else{
+        cout<<n-n%x+y-x<<endl;
+    }
+}
+return 0;
+}