CareerCup Median of three numbers

Given tree integers a, b,c. Write a function: int median (int a,int b,int c) to get the median number among a,b,c. Can not use sort, the times of integer operations (e.g. compare, + - * /, bit computing) the less the better. Analyze the best and the worst situation.

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int median(int a, int b, int c){
   int m = min(a,b);
   int n = min(b,c);
   int o = min(c,a);
   return(m^n^o);
}