문제

입출력 및 예제들

코드 작성
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
public class Main {
public static int cnt = 0, target = 0;
public static int[] output;
public static boolean isOut = false;
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine());
int num = Integer.parseInt(st.nextToken());
target = Integer.parseInt(st.nextToken());
int[] arr = new int[num + 1];
arr[0] = 0;
st = new StringTokenizer(br.readLine());
for (int i = 1; i < arr.length; i++) arr[i] = Integer.parseInt(st.nextToken());
heapSort(arr);
if (!isOut) {
System.out.print(-1);
}
}
public static void swap (int[] arr, int a, int b){
cnt++;
int tmp = arr[a];
arr[a] = arr[b];
arr[b] = tmp;
if(cnt == target){
StringBuilder sb = new StringBuilder();
for (int i = 1; i < arr.length; i++) {
sb.append(arr[i]);
sb.append(" ");
}
System.out.print(sb.toString());
isOut = true;
}
}
public static void heapSort(int[] arr) {
buildMinHeap(arr, arr.length - 1);
for (int i = arr.length - 1; i > 1 ; i--) {
swap(arr, 1 , i);
heapify(arr, 1, i - 1);
}
}
public static void buildMinHeap(int[] arr, int num) {
for (int i = num / 2; i >= 1 && !isOut; i--) {
heapify(arr, i, num);
}
}
public static void heapify(int[] arr, int k, int num) {
int left = 2 * k;
int right = 2 * k + 1;
int smaller = -1;
if (right <= num) {
smaller = arr[left] < arr[right] ? left : right;
} else if (left <= num) {
smaller = left;
} else {
return;
}
if (arr[smaller] < arr[k]) {
swap(arr,k,smaller);
heapify(arr, smaller, num);
}
}
}
Etc
이것도 구글링을 통해 얻은 코드라 gpt의 도움을 받아 해석해보았다..