Revert "Optimize performance using dict"
Revert "Optimize performance using dict"

This reverts commit a92999d1a545514f981a61a2aabf4f58d9453f57.

We will work on optimization later.

okuta/chainer,niboshi/chainer,keisuke-umezawa/chainer,hvy/chainer,wkentaro/chainer,ktnyt/chainer,chainer/chainer,okuta/chainer,ktnyt/chainer,chainer/chainer,hvy/chainer,jnishi/chainer,keisuke-umezawa/chainer,wkentaro/chainer,niboshi/chainer,jnishi/chainer,tkerola/chainer,okuta/chainer,ktnyt/chainer,wkentaro/chainer,keisuke-umezawa/chainer,hvy/chainer,chainer/chainer,chainer/chainer,keisuke-umezawa/chainer,jnishi/chainer,okuta/chainer,niboshi/chainer,niboshi/chainer,ktnyt/chainer,pfnet/chainer,hvy/chainer,jnishi/chainer,wkentaro/chainer