Given a set of positive integers and a target sum S, the sum of subset problem is to determine if there exists a subset of the integers whose sum equals S. The algorithm uses a two dimensional table t, where t[i,j] is true if there is a subset that sums to j using the first i elements of the set. It iterates through the elements, setting t[i,j] to true if t[i-1,j] is already true or t[i-1,j-w[i]] is true, where w[i] is the current element. It returns t[n,m] which indicates if a subset summing to S exists.