B_1068

Algorithm_Min/Baek1068.java

@@ -0,0 +1,82 @@
+package 알고_민규;
+
+import java.util.ArrayList;
+import java.util.Scanner;
+public class Baek1068 {
+ static ArrayList<ArrayList<Integer>> ad_list = new ArrayList<ArrayList<Integer>>();
+ static boolean[] visit;
+ static int root;
+ static int goal;
+ static int count=0;
+ public static void main(String[] args){
+ Scanner sc = new Scanner(System.in);
+ int N = sc.nextInt();
+ visit = new boolean[N];
+ for(int i = 0 ; i < N ; i++) ad_list.add(new ArrayList<Integer>());
+ for(int i = 0 ; i < N ; i++) {
+ int a = sc.nextInt();
+ if(a == -1) {
+ root = i;
+ continue;
+ }
+
+ ArrayList<Integer> tmp=ad_list.get(a);
+ tmp.add(i);
+ }
+ goal = sc.nextInt();
+
+ if(root == goal) {
+ System.out.println(0);
+ return;
+ }
+
+ breaking(root,false);
+
+// for(int i = 0 ; i < N ; i++) {
+// System.out.println(ad_list.get(i));
+// }
+
+ chcking(root);
+
+ System.out.println(count);
+ }
+ public static void breaking(int g,boolean check) {
+ ArrayList<Integer> list = ad_list.get(g);
+ for(int i = 0 ; i < list.size() ; i++) {
+ int a = list.get(i);
+ if(g == goal || check) {
+ ad_list.set(g,new ArrayList<Integer>());
+ breaking(a,true);
+ }else {
+ breaking(a,false);
+ }
+ }
+ }
+ public static void chcking(int g) {
+
+ ArrayList<Integer> list = ad_list.get(g);
+ if(list.size() == 0 && g!=goal) {
+ //System.out.println(g);
+ count++;
+ }
+ else {
+ for(int i = 0 ; i < list.size() ; i++) {
+ int a = list.get(i);
+ chcking(a);
+ }
+ }
+ }
+// public static void chcking(int g) {
+// ArrayList<Integer> list = ad_list.get(g);
+// if(list.size() == 0 && g!=goal) {
+// //System.out.println(g);
+// count++;
+// }
+// else {
+// for(int i = 0 ; i < list.size() ; i++) {
+// int a = list.get(i);
+// chcking(a);
+// }
+// }
+// }
+}