Question

How to find a number in array that appears once in C

Answer 1

#include <stdio.h>
#include <stdbool.h>
 
bool number_exist_few_times(int arr[], int len, int number, int index) {
    for (int i = 0; i < len; i++) {
        if (arr[i] == number && i != index) {
            return true;
        }
    }
    return false;
}
 
int get_single_number(int arr[], int len) { 
    for (int i = 0; i < len; i++) {
        if (!number_exist_few_times(arr, len, arr[i], i))
            return arr[i];
    }
    return -1;
} 
   
int main() 
{ 
   int arr[] = {3, 2, 1, 2, 3, 3, 1, 5, 9, 7, 7, 9, 9}; 
   int len = sizeof(arr) / sizeof(arr[0]); 
     
   printf("%i", get_single_number(arr, len)); 
} 
 
 
 
/*
run:
 
5
 
*/

 

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