chore(C): add shuffle array algorithm (#827)

Co-authored-by: Ivan Kirspu <luneyune@users.noreply.github.com>

algorithms/C/README.md

@@ -5,6 +5,7 @@
 - [Even and Odd](arrays/even-and-odd.c)
 - [Unique Elements in an array](arrays/unique-elements-in-an-array.c)
 - [Reverse an array](arrays/reverse-array.c)
+- [Shuffle an array](arrays/shuffle_array.c)
 - [Maximum difference](arrays/maximum-difference.c)
 - [Largest Element](arrays/largestElement.c)
 - [Second Largest Element](arrays/secondLargestElement.c)

algorithms/C/arrays/shuffle_array.c

@@ -0,0 +1,54 @@
+/*
+
+[PROBLEM]: Given an array, of size n, shuffle it.
+
+[TIME COMPLEXITY]: O(N)
+
+[SAMPLE OF OUTPUT]:
+
+Before shuffling:
+1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 
+After shuffling:
+9 6 4 10 11 15 5 3 12 1 7 14 2 8 13 
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+void swap(int *a, int *b) // Swap values between *a and *b
+{
+    int tmp = *a;
+    *a = *b;
+    *b = tmp;
+}
+
+void shuffle(int *array, int size) // Randomly shuffles given array
+{
+    for (int i = 0; i < size; i++) {
+        swap(array + i, array + (rand() % size)); // Each element swaps with another random element
+    }
+}
+
+void print_array(int *array, int size) // Printing array
+{
+    for (int i = 0; i < size; i++) {
+        printf("%d ", array[i]);
+    }
+    putchar('\n');
+}
+
+int main()
+{
+    srand(time(NULL)); // Setup of random seed for random generation
+    int array[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
+    printf("Before shuffling:\n");
+    print_array(array, 15);
+
+    shuffle(array, 15);
+    printf("After shuffling:\n");
+    print_array(array, 15);
+
+    return 0;
+}