public class Practice1_1 {
void permutation(int[] arr, int depth, int n, int r) {
if (depth == r) {
for (int i = 0; i < n; i++) {
System.out.println(arr[i] + " ");
}
System.out.println();
return;
}
for (int i = depth; i < r; i++) {
swap(arr, depth, i);
permutation (arr,depth + 1, n, r);
swap(arr, depth, i);
}
}
void swap (int[] arr, int depth, int index) {
int tmp = arr[depth];
arr[depth] = arr[index];
arr[index] = tmp;
}
public static void main(String[] args) {
int[] arr = {1, 2, 3, 4};
Practice1 p = new Practice1();
p.permutation(arr, 0, 4, 3);
}
}
결과값
=> 틀림
public class Practice1_2 {
void permutation(int[] arr, int depth, int n, int r) {
if (depth == r) {
for (int i = 0; i < r; i++) {
System.out.print(arr[i] + " ");
}
System.out.println();
return;
}
for (int i = depth; i < n; i++) {
swap(arr,depth,i);
permutation(arr, depth + 1, n, r);
swap(arr,depth,i);
}
}
void swap (int[] arr, int depth, int a) {
int tmp = arr[depth];
arr[depth] = arr[a];
arr[a] = tmp;
}
public static void main(String[] args) {
int[] arr = {1, 2, 3, 4};
Practice1 p = new Practice1();
p.permutation(arr, 0, 4, 3);
}
}
결과값
=> 정답
public class Practice1_1 {
void permutation(int[] arr, int depth, int n, int r, boolean[] visited, int[] out) {
if (depth == r) {
System.out.println(Arrays.toString(out));
return;
}
for (int i = 0; i < n; i++) {
if (visited[i] != true) {
visited[i] = true;
out[depth] = arr[i];
permutation(arr,depth + 1, n, r, visited, out);
visited[i] = false;
}
}
}
public static void main(String[] args) {
int n = 4;
int r = 3;
int[] arr = {1, 2, 3, 4};
boolean[] visited = new boolean[n];
int[] out = new int[r];
Practice2 p = new Practice2();
p.permutation(arr, 0, n, r, visited, out);
}
}
결과값
=> 정답