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Main.java
51 lines (36 loc) · 1.11 KB
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Main.java
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import java.io.*;
import java.util.StringTokenizer;
/**
* BOJ#1182 부분집합의 합
* https://www.acmicpc.net/problem/1182
*/
public class Main {
static int N;
static int S;
static int cnt = 0;
static int[] numArr = new int[21];
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine());
N = Integer.parseInt(st.nextToken());
S = Integer.parseInt(st.nextToken());
st = new StringTokenizer(br.readLine());
for (int i = 0; i < N; i++) {
numArr[i] = Integer.parseInt(st.nextToken());
}
solve(0, 0);
// S가 0인 경우 공집합도 포함되므로 개수에서 -1을 빼준다.
if (S == 0) {
cnt -= 1;
}
System.out.println(cnt);
}
static void solve(int sum, int step) {
if (step == N) {
if (sum == S) cnt++;
return;
}
solve(sum + numArr[step], step + 1);
solve(sum, step + 1);
}
}