For a minimalist cutting algorithm

Example: there are N in different length of raw materials (infinite) to the amount of each raw material, needs to cut a M a target size, write algorithms, find out the most saving material cutting method,

A practical example: there are three different lengths of raw material is 5 meters respectively, 6 m, 8 m, need to cut become the size: 1.5 m, 1.5 m, 1.5 m, 1.5 m, 2 m, 2 m, 2 m, 2 m, 3 m, 3 m, 3 m, 4 m, 5.5 meters, 5.5 meters, write algorithm, find the cutting way of saving material, (the above data are for example)