Function to build the segment tree
static void build ( int node , int l , int r , int a [ ] ) { if ( l == r ) seg [ node ] = a [ l ] ; else { int mid = ( l + r ) / 2 ; build ( 2 * node , l , mid , a ) ; build ( 2 * node + 1 , mid + 1 , r , a ) ; seg [ node ] = ( seg [ 2 * node ] seg [ 2 * node + 1 ] ) ; } }