从n个数挑k个，和等于m

/** * find k from n, to make sum(k) equals m. * */public class SubSumEquals {public void containValue(int[] a, int value){assert(true);for(int i=1; i<=a.length; i++){int[] b = new int[i];find(a, a.length, i, value, b);}}private void find(int[] a, int n, int m, int value, int[] b){assert(true);for(int i=n; i>=m; i--){b[m-1] = i - 1 ;if(m > 1){find(a, i-1, m-1, value, b);}else{testEquals(a, b, value);}}}private void testEquals(int[] a, int[] b, int value){assert(true);int sum = 0;for(int i=0; i<b.length; i++){sum += a[b[i]];}if(sum == value){for(int j=0; j<b.length; j++){System.out.print(a[b[j]] + " ");}System.out.println();}}/** * @param args */public static void main(String[] args) {int[] a = {3,2,4,3,6};SubSumEquals sse = new SubSumEquals();sse.containValue(a, 6);}}