递归出口如何设计啊？

public class sumCnt { public static void main(String[] args){ int[] a = {1, 2, 4, 3, 5}; System.out.println(f(a.length - 1, 4, a)); } // n: 遍历数组a下标,从0到a.length-1; public static int f(int n, int m, int[] a){ if(n == 0){ return a[n] == m ? 1: 0; } if(a[n] == m){ return f(n-1, m, a) + 1; }else if(a[n] < m){ return f(n-1, m, a) + f(n-1, m - a[n], a); }else{ return f(n-1, m, a); } } } 仅供参考哈！