Sock Merchant problem

Author: massg

Hackerrank/SockMerchant.c

@@ -0,0 +1,117 @@
+// Link : https://www.hackerrank.com/challenges/sock-merchant/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=warmup
+
+#include <assert.h>
+#include <limits.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+char* readline();
+char** split_string(char*);
+
+// Complete the sockMerchant function below.
+int sockMerchant(int n, int ar_count, int* ar) {
+    int freq[101]={};
+    int col;
+    for(int i=0;i<n;i++)
+    {
+        col = *(ar+i);
+        freq[col]++;
+    }
+    int pair = 0;
+    for(int i = 0; i < 101; i++){
+         pair += freq[i] / 2;
+     }
+     return pair;
+}
+
+int main()
+{
+    FILE* fptr = fopen(getenv("OUTPUT_PATH"), "w");
+
+    char* n_endptr;
+    char* n_str = readline();
+    int n = strtol(n_str, &n_endptr, 10);
+
+    if (n_endptr == n_str || *n_endptr != '\0') { exit(EXIT_FAILURE); }
+
+    char** ar_temp = split_string(readline());
+
+    int* ar = malloc(n * sizeof(int));
+
+    for (int i = 0; i < n; i++) {
+        char* ar_item_endptr;
+        char* ar_item_str = *(ar_temp + i);
+        int ar_item = strtol(ar_item_str, &ar_item_endptr, 10);
+
+        if (ar_item_endptr == ar_item_str || *ar_item_endptr != '\0') { exit(EXIT_FAILURE); }
+
+        *(ar + i) = ar_item;
+    }
+
+    int ar_count = n;
+
+    int result = sockMerchant(n, ar_count, ar);
+
+    fprintf(fptr, "%d\n", result);
+
+    fclose(fptr);
+
+    return 0;
+}
+
+char* readline() {
+    size_t alloc_length = 1024;
+    size_t data_length = 0;
+    char* data = malloc(alloc_length);
+
+    while (true) {
+        char* cursor = data + data_length;
+        char* line = fgets(cursor, alloc_length - data_length, stdin);
+
+        if (!line) { break; }
+
+        data_length += strlen(cursor);
+
+        if (data_length < alloc_length - 1 || data[data_length - 1] == '\n') { break; }
+
+        size_t new_length = alloc_length << 1;
+        data = realloc(data, new_length);
+
+        if (!data) { break; }
+
+        alloc_length = new_length;
+    }
+
+    if (data[data_length - 1] == '\n') {
+        data[data_length - 1] = '\0';
+    }
+
+    data = realloc(data, data_length);
+
+    return data;
+}
+
+char** split_string(char* str) {
+    char** splits = NULL;
+    char* token = strtok(str, " ");
+
+    int spaces = 0;
+
+    while (token) {
+        splits = realloc(splits, sizeof(char*) * ++spaces);
+        if (!splits) {
+            return splits;
+        }
+
+        splits[spaces - 1] = token;
+
+        token = strtok(NULL, " ");
+    }
+
+    return splits;
+}