If you want a sparse adjacency matrix, call SPARSE.
edgeList = [1 2; 2 3; 2 4];
adj = sparse(edgeList(:, 1), edgeList(:, 2), 1, 4, 4);
Note that if you have a repeated edge in your edgeList, the corresponding element of adj will be greater than 1.
If you want a full adjacency matrix, either convert the sparse adjacency matrix to FULL or call ACCUMARRAY.