The time complexity of pre-processing stage is O(n∗log n), hence the
pre-processing stage cannot raise the time complexity in the overall
process of triangulation. After the pre-processing stage, the input
polygon has been already converted into multiple pieces of monotone
polygons. The monotone triangulation algorithm is applied to the
multiple monotone polygons to reduce the time complexity of triangulation
stage fromO(n2) toO(m∗nlogn)wheremis the number ofmonotone
polygons in G and m is far less than n. The monotone triangulation
algorithm is presented in Algorithm 2.