//@Description Sketch to swap two bit arrays without using extra storage. int W = 32; void swap(ref bit[W] x, ref bit[W] y){ int t = ??; repeat(t){ if(??){ x = x ^ y;}else{ y = x ^ y; } } } harness void main(bit[W] x, bit[W] y){ bit[W] tx = x; bit[W] ty = y; swap(x, y); assert x==ty && y == tx; }