feat(solutions): add find-outlier-number/c/function

challenges/find-outlier-number/solutions/c/function/README.md

@@ -0,0 +1,3 @@
+# find-outlier-number/c/function
+
+Created by [@Divlo](https://github.com/Divlo) on 30 September 2021.

challenges/find-outlier-number/solutions/c/function/solution.c

@@ -0,0 +1,47 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+bool is_odd(int number) {
+  return number % 2 == 1;
+}
+
+int find_outlier_number(int* numbers, size_t length) {
+  int outlier_number;
+  int* odd_numbers = malloc(length * sizeof(int));
+  int* even_numbers = malloc(length * sizeof(int));
+  size_t odd_length = 0;
+  size_t even_length = 0;
+  for (size_t index = 0; index < length; index++) {
+    if (is_odd(numbers[index])) {
+      odd_numbers[odd_length] = numbers[index];
+      odd_length++;
+    } else {
+      even_numbers[even_length] = numbers[index];
+      even_length++;
+    }
+  }
+  if (odd_length == 1) {
+    outlier_number = odd_numbers[0];
+  } else {
+    outlier_number = even_numbers[0];
+  }
+  free(odd_numbers);
+  free(even_numbers);
+  return outlier_number;
+}
+
+int main() {
+  size_t length = 0;
+  int number;
+  int* numbers = malloc(sizeof(int));
+  do {
+    scanf("%d", &number);
+    numbers = realloc(numbers, sizeof(int) * (length + 1));
+    numbers[length] = number;
+    length++;
+  } while (fgetc(stdin) != EOF);
+  printf("%d\n", find_outlier_number(numbers, length));
+  free(numbers);
+  return EXIT_SUCCESS;
+}