Convex Hulls of Finite Sets of Poin ts in Two and Three Dimensions The convex hulls of sets of n poin ts in two and three dimensions can be determined with O(n log n) operations. The presented algorithms use the "divide and conquer" technique and recursively apply a merge procedure for two nonin tersecting convex hulls. Since any convex hull algorithm requires at least O(n log n) operations, the time complexity of the proposed algorithms is optimal within a multiplicative constant. CACM February, 1977 Preparata, F. P. Hong, S. J. computational complexity, convex hull, optimal algorithms, planar set of poin ts, spatial set of poin ts 4.49 5.25 5.32 CA770203 JB December 30, 1977 2:47 AM 2997 4 2997 2737 5 2997 2997 5 2997 2997 5 2997 2997 5 2997 3151 5 2997 2997 6 2997