feat: day8 easy solution

Easy/Day8/Solution.cpp

@@ -1 +1,30 @@
-// Write your code here
+#include <bits/stdc++.h>
+using namespace std;
+long long BinExpo(long long a, long long b, long long m)
+{
+    // basse case
+    if (b == 0)
+        return 1;
+    // recursive case
+    long long res = BinExpo(a, b / 2, m);
+    if (b & 1) // if b is odd
+    {
+        return ((a * (res % m)) % m * (res % m)) % m;
+    }
+    else
+    {
+        return (res * res) % m;
+    }
+}
+int main()
+{
+    long long m = 1e9 + 7;
+    int t;
+    cin >> t;
+    while (t--)
+    {
+        long long a, b;
+        cin >> a >> b;
+        cout << BinExpo(a, b, m) << endl;
+    }
+}