Practice #1
Lesson 10 of 14 in Coddy's Hash Tables - Data Structures Series #4 course.
Challenge
EasyWrite a function firstRepeated that gets an integer array arr and returns the first element that appears more than once when you scan from left to right.
If no element repeats, return -1.
You must use the HashMap class provided in hashmap.<ext> — do not use language built-ins like sets, dicts, or maps.
Try it yourself
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "solution.h"
int main() {
char line[8192];
if (!fgets(line, sizeof(line), stdin)) line[0] = '\0';
int arr[4096];
int n = 0;
char* tok = strtok(line, " \t\r\n");
while (tok) { arr[n++] = atoi(tok); tok = strtok(NULL, " \t\r\n"); }
int r = firstRepeated(arr, n);
printf("%d\n", r);
return 0;
}