All numbers are present 3 times except one number which is there only once. Find that number.

#include<stdio.h>

int findUnique(int a[],int len){
int i,j;
int x=0;
int y;
int fact = 1;
for(i=0;i<32;i++){
y = 0;
for(j=0;j<len;j++){
y += a[j] & (1<<i);
}
x += fact * (y%3);
fact *= 2;
}
return x;
}

int main(){
int a[] = {1,2,3,2,3,4,3,1,1,2};
int n = findUnique(a,sizeof(a)/sizeof(a[0]));
printf("%d",n);
return 0;
}