Help me in solving MISSP problem

help
,
1

My issue

my code is getting runtime error how to solve it

My code


#include<stdio.h>
#include <stdlib.h>
void main()
{
    int t;
    scanf("%d",&t);
    int n;
   
    
    for(int i=t;i>0;i--){
    scanf("%d",&n);
     int *arr = (int *)malloc(n * sizeof(int));
         for(int k=0;k<n+1;k++){
             scanf("%d",&arr[k]);
         }
         for(int u=0;u<n;u++){int r=0;
         for(int h=0;h<n;h++){
             if(arr[u]==arr[h]){
                 r++;
             }
             }
             if (r%2==1){
                 printf("%d",arr[u]);
             }
         }
        free(arr);
    }

}

Learning course: Arrays, Strings & Sorting
Problem Link: Chef and Dolls Practice Problem in - CodeChef

2

@tejas_suddala
just calculate the xor of the whole array.