function which find number
int singleNumber ( int nums [ ] , int n ) { map < int , int > m ; long sum1 = 0 , sum2 = 0 ; for ( int i = 0 ; i < n ; i ++ ) { if ( m [ nums [ i ] ] == 0 ) { sum1 += nums [ i ] ; m [ nums [ i ] ] ++ ; } sum2 += nums [ i ] ; }