Building corners: How to connect 2 walls with a straight corner Hello I'm strugling with this task that I suppose should be quite easy :P

I've two walls with the same shapes and profiles, those two should be placed at the corner of a building, I'm looking for a way to close the gap between the walls. I could probably do it manually, but I'm pretty sure it should be done in an automatic way using some techniques or tools that I'm not aware of. 

Attached you find an image with top and perspective views, in green the result I'd like to obtain (sorry... it has badly hands-drawn) probably it is not very clear from the image, but I'd like to close the corner continuing the wall shape having the two walls "merged" at 90 degs.

Any idea?
3 methods (or surely more):

1/Bridge edge loops (1):


Select the corresponding vertices
CtrlE then bridge edge loops
Select edges from bottom to top CtrlAltRMB
Scale 0 using individual origins as pivot
Remove doubles
Select the corner
Scale by 2 for X and Y from the cursor placed at the inner corner




2/Bridge edge loops (2):


Select the corresponding vertices
CtrlE then bridge edge loops
Set number of cuts to 1
Set interpolation to blend surface
Set smoothness to sqrt(2)




3/Rotation


Select the wanted vertices on one side
Place the cursor at the inner corner
Set the pivot to 3D cursor
Rotate 45 degrees
Scale sqrt(2) for X and Y
Do the same for the other side