dancing link

My purpose is to discuss an extremely simple technique that deserves to be better known. Suppose x points to an element of a doubly linked list; let L[x] and R[x] point to the predecessor and successor of that element. Then the operations L R[x] ← L[x], R L[x] ← R[x] (1) remove x from the list; every programmer knows this. But comparatively few programmers have realized that the subsequent operations