Combination Sum IV (Backpack VI

Java

public class Solution {
    /**
     * @param nums: an integer array and all positive numbers, no duplicates
     * @param target: An integer
     * @return: An integer
     */
		public int backPackVI(int[] A, int m) {
			int n = A.length;
			int[] f = new int[m + 1];
			f[0] = 1;
			int i, j;
			for (i = 1; i <=m; ++i) {
				f[i] = 0; 
				for (j = 0; j < n; ++j) {
					if (A[j] <= i) {
						f[i] += f[i - A[j]];
					}
				}
			}
				return f[m];
		}
}