From 079938ea7c142b99f1e48dc9ebfb418fc3d40f03 Mon Sep 17 00:00:00 2001
From: Krishna Vedala <krishna.vedala@ieee.org>
Date: Mon, 30 Mar 2020 15:43:16 -0400
Subject: [PATCH 1/2] algorithm from
 http://www.cplusplus.com/forum/beginner/68694/

---
 project_euler/Problem 16/sol1.c | 55 +++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 project_euler/Problem 16/sol1.c

diff --git a/project_euler/Problem 16/sol1.c b/project_euler/Problem 16/sol1.c
new file mode 100644
index 00000000..6c307a40
--- /dev/null
+++ b/project_euler/Problem 16/sol1.c	
@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+int main(int argc, char **argv)
+{
+    const double tmp = log(10) / log(2); /* required to get number of digits */
+    unsigned long MAX_NUM_DIGITS;
+    uint8_t *digits = NULL;              /* array to store individual digits. index 0 = units place */
+    int N = 1000, sum = 0;
+
+    if (argc == 2)
+        N = atoi(argv[1]);
+
+    MAX_NUM_DIGITS = (N + tmp) / tmp;
+    
+    digits = calloc(MAX_NUM_DIGITS, sizeof(uint8_t));
+    digits[0] = 1;
+
+    if (!digits)
+    {
+        perror("Unable to allocate memory!");
+        return -1;
+    }
+
+    for (int i = 0; i < N; i++)
+    {
+        int carry = 0;
+        for (int j = 0; j < MAX_NUM_DIGITS; j++)
+        {
+            digits[j] = (digits[j] << 1) + carry;   /* digit * 2 + carry */
+            // printf("\t value: %d\t", digits[j]);
+            if (digits[j] > 9)
+            {
+                carry = 1;
+                digits[j] -= 10;
+            } else
+                carry = 0;
+            // printf("carry: %d\t value: %d\n", carry, digits[j]);
+            
+            /* accumulate sum for last multiplication */
+            if (i == N - 1)
+                sum += digits[j];
+        }
+    }
+
+    printf("2^%d = ", N);
+    for(int i = MAX_NUM_DIGITS - 1; i >= 0; i--)
+        putchar(digits[i] + 0x30);
+    printf("\n\t Sum: %d\t Num. digits: %lu\n", sum, MAX_NUM_DIGITS);
+
+    free(digits);
+    return 0;
+}
\ No newline at end of file

From 9f25309c90d6f74fece243a3d4ef598ecd74bc8b Mon Sep 17 00:00:00 2001
From: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Date: Mon, 30 Mar 2020 19:43:54 +0000
Subject: [PATCH 2/2] updating DIRECTORY.md

---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 5ef05421..ba42ac0e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -223,6 +223,8 @@
     * [Sol](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2006/sol.c)
   * Problem 07
     * [Sol](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2007/sol.c)
+  * Problem 16
+    * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2016/sol1.c)
 
 ## Searching
   * [Binary Search](https://github.com/TheAlgorithms/C/blob/master/searching/Binary_Search.c)