package algorithm;

public class SubsMain {

static int N = 4, R = 3, C = 0;

static int[] a = { 1, 2, 3, 4 }, b = new int[R];

static boolean[] v = new boolean[N];

static void subs(int cnt, int sum) {

if (cnt == N) {

for (int i = 0; i < N; i++) {

System.out.print((v[i] ? a[i] : "X") + " ");

}

System.out.println("sum=" + sum);

C++;

return;

}

v[cnt] = true;

subs(cnt + 1, sum + a[cnt]);

v[cnt] = false;

subs(cnt + 1, sum);

}

static void subs(int cnt) {

if (cnt == N) {

for (int i = 0; i < N; i++) {

System.out.print((v[i] ? a[i] : "X") + " ");

}

System.out.println();

C++;

return;

}

v[cnt] = true;

subs(cnt + 1);

v[cnt] = false;

subs(cnt + 1);

}

public static void main(String[] args) throws Exception {

C = 0;

// subs(0); // 2^n 부분집합(subsets, power set)

subs(0, 0);

System.out.println(C);

}

}