APS
백준1182_부분집합의 합
ChoiSH313
2019. 2. 3. 14:32
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package backjoon;
import java.util.Scanner;
/**
* 알고리즘 경우의 수 부분집합 게시글 참고!!
*/
public class b1182 {
static int cnt = 0;
public static void sum(int[] arr, int[] arr_index, int size, int N, int S, int index) {
int sum = 0;
for (int i = 0; i < size; i++) {
int j = arr_index[i];
sum += arr[j];
}
if (size != 0) {
if (sum == S) {
cnt++;
}
}
}
public static void subset(int[] arr, int[] arr_index, int size, int N, int S, int index) {
// 인덱스로 사용할 부분집합만 만들어줌
if (N == index) {
sum(arr, arr_index, size, N, S, index);
return;
}
arr_index[size] = index;
subset(arr, arr_index, size + 1, N, S, index + 1);
subset(arr, arr_index, size, N, S, index + 1);
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int N = sc.nextInt();
int S = sc.nextInt();
int[] arr = new int[N];
int[] arr_index = new int[N];
for (int i = 0; i < arr.length; i++) {
arr[i] = sc.nextInt();
}
subset(arr, arr_index, 0, N, S, 0);
System.out.println(cnt);
}
}
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