[Edu] Update p32 bank conflict

MODULAR_ORIG_COMMIT_REV_ID: 4accc83c26355880dd699038243e2a5600e2d0a8

Author: dunnoconnor

problems/p32/p32.mojo

@@ -72,16 +72,16 @@ def two_way_conflict_kernel(
     Each bank serves 2 threads, doubling access time.
     """
 
-    # Shared memory buffer - stride-2 access pattern creates conflicts
+    # Sized to 2*TPB so stride-2 writes don't alias (threads i and i+TPB/2).
     var shared_buf = stack_allocation[
         dtype=dtype, address_space=AddressSpace.SHARED
-    ](row_major[TPB]())
+    ](row_major[2 * TPB]())
 
     var global_i = block_dim.x * block_idx.x + thread_idx.x
     var local_i = thread_idx.x
 
     # CONFLICT: stride-2 access creates 2-way bank conflicts
-    var conflict_index = (local_i * 2) % TPB
+    var conflict_index = local_i * 2
 
     # Load with bank conflicts
     if global_i < size: