diff --git a/theory/data_structure/arrays.cpp b/theory/data_structure/arrays.cpp
new file mode 100644
index 0000000..9683168
--- /dev/null
+++ b/theory/data_structure/arrays.cpp
@@ -0,0 +1,31 @@
+#include <iostream>
+
+//Reverse an array
+void reverseArray(int *v, int size) {
+
+    int tmp, a = 0;
+    for(int i = size-1; i>=size/2; --i) {
+        tmp = v[i];
+        v[i] = v[a];
+        v[a] = tmp;
+        a++;
+    }
+
+}
+
+int main(){
+
+    int arr[] = {0,1,2,3,4,5,6,7,8,9};
+    int n = 10;
+    reverseArray(arr, n);
+
+}
+
+
+
+
+
+
+
+
+
diff --git a/theory/greedy/busyman.cpp b/theory/greedy/busyman.cpp
new file mode 100644
index 0000000..f3f61bb
--- /dev/null
+++ b/theory/greedy/busyman.cpp
@@ -0,0 +1,53 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+
+// Creating a template to sort the vector of pairs
+// using the second int element
+bool sortbysec(const std::pair<int,int> &a, const std::pair<int,int> &b) {
+    return (a.second < b.second);
+}
+
+// function to count the max of activites that we can make
+// Picking the first, after sorting te vector, to use as base
+int findMax(std::vector<std::pair<int, int>> v) {
+
+    std::sort(v.begin(),v.end(),sortbysec);
+    
+    int count = 1, temp = v[0].second;
+    for(int i = 1; i < v.size(); ++i) {
+        if(v[i].first >= temp && v[i].second > temp) {
+            count++;
+            temp = v[i].second;
+        }
+    }
+
+    return count;
+
+}
+
+int main(){
+
+
+    std::vector<std::pair<int, int>> act;
+    int n, t;
+    std::cin >> n;
+
+    for(int i = 0; i < n; ++i) {
+
+        std::cin >> t;
+        for(int j = 0; j < t; ++j) {
+            int s, e;
+            std::cin >> s >> e;
+            act.emplace_back(std::make_pair(s,e));
+        }
+            
+        int count = findMax(act);
+        std::cout << count << std::endl;
+
+    }
+
+}
+
+
diff --git a/theory/greedy/indianCoinChange.cpp b/theory/greedy/indianCoinChange.cpp
new file mode 100644
index 0000000..75d53a0
--- /dev/null
+++ b/theory/greedy/indianCoinChange.cpp
@@ -0,0 +1,59 @@
+/*
+
+    Problem: Suposse you want to make a change of some
+    Indian Rupees using minimum number of coins / notes
+
+    Denominatios = [1,2,5,10,20,50,100,500,2000]
+
+
+    Input
+    273
+
+    Output
+    100+100+50+20+2+1
+
+*/
+
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+std::vector<int> denomination = {1,2,5,10,20,50,100,500,2000};
+
+
+void findMin(int n) {
+
+    std::vector<int> ans;
+
+    for(int i = denomination.size()-1; i >= 0; --i) {
+
+        while(n >= denomination[i]) {
+            n -= denomination[i];
+            ans.push_back(denomination[i]);
+        }
+    }
+
+
+    for(auto x: ans)
+        std::cout << x << " ";
+    std::cout << std::endl;
+
+}
+
+
+int main(){
+
+    int n;
+    std::cin >> n;
+
+    findMin(n);
+
+
+}
+
+
+
+
+
+
+