Factorials of large numbers

Author: sachuverma

DSA Crack Sheet/README.md

@@ -22,6 +22,7 @@
 - [Common elements](https://practice.geeksforgeeks.org/problems/common-elements1132/1# "view question") - [Cpp Solution](./solutions/Common%20elements.cpp)
 - [Rearrange array in alternating positive & negative items with O(1) extra space](https://www.geeksforgeeks.org/rearrange-array-alternating-positive-negative-items-o1-extra-space/ "view topic") - [Cpp Solution](./solutions/Rearrange%20array%20in%20alternating%20positive%20&%20negative%20items%20with%20O(1)%20extra%20space.cpp)
 - [Subarray with 0 sum](https://practice.geeksforgeeks.org/problems/subarray-with-0-sum-1587115621/1# "view question") - [Cpp Solution](./solutions/Subarray%20with%200%20sum.cpp)
+- [Factorials of large numbers](https://practice.geeksforgeeks.org/problems/factorials-of-large-numbers/0# "view question") - [Cpp Solution](./solutions/Factorials%20of%20large%20numbers.cpp)
 - []( "view question") - [Cpp Solution](./solutions/.cpp)
 
 <!-- - []( "view question") - [Cpp Solution](./solutions/) -->

DSA Crack Sheet/solutions/Factorials of large numbers.cpp

@@ -0,0 +1,68 @@
+/*
+Factorials of large numbers
+===========================
+
+Given an integer, the task is to find factorial of the number.
+
+Input:
+The first line of input contains an integer T denoting the number of test cases.  
+The first line of each test case is N,the number whose factorial is to be found
+
+Output:
+Print the factorial of the number in separate line.
+
+Constraints:
+1 ≤ T ≤ 100
+1 ≤ N ≤ 1000
+
+Example:
+Input:
+3
+5
+10
+2
+
+Output:
+120
+3628800
+2
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+  int t;
+  cin >> t;
+  while (t--)
+  {
+    int n;
+    cin >> n;
+    string ans = "1";
+    for (int i = 2; i <= n; ++i)
+    {
+      int carry = 0;
+      for (auto &ch : ans)
+      {
+        int num = ch - '0';
+        num = i * num;
+        num += carry;
+        int digit = num % 10;
+        ch = (digit + '0');
+        carry = num / 10;
+      }
+
+      while (carry)
+      {
+        int digit = carry % 10;
+        carry = carry / 10;
+        ans += to_string(digit);
+      }
+    }
+
+    reverse(ans.begin(), ans.end());
+    cout << ans << endl;
+  }
+  return 0;
+}