Buyers snapped up more than 4,000 single-family homes in Massachusetts last month, pushing the number of statewide sales for the first 10 months of 2012 above the total for all of last year.

Warren Group, a Boston real estate tracking company, reported Tuesday that home sales in October increased by 21 percent, to 4,044, compared with the same month last year, reflecting increased optimism about the state’s housing market.