[20250213] BOJ / G3 / K진 트리 / 권혁준

khj20006/202502/13 BOJ G3 K진 트리.md

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+```java
+
+import java.util.*;
+import java.io.*;
+
+
+class Main {
+
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+
+	// Additional field
+	static long N, K, Q;
+
+	public static void main(String[] args) throws Exception {
+
+		ready();
+		solve();
+
+		bwEnd();
+	}
+
+	static void ready() throws Exception{
+
+		nextLine();
+		N = nextLong();
+		K = nextLong();
+		Q = nextLong();
+
+	}
+
+	static void solve() throws Exception{
+
+		while(Q-- > 0) {
+			nextLine();
+			long x = nextLong(), y = nextLong();
+			bw.write(dist(x-1,y-1) + "\n");
+		}
+
+	}
+
+	static long dist(long x, long y) throws Exception{
+		if(K == 1) return Math.abs(x-y);
+		List<Long> X = find(x), Y = find(y);
+		int i = X.size()-1, j = Y.size()-1;
+
+		while(i>=0 && j>=0 && X.get(i).equals(Y.get(j))){
+			i--;
+			j--;
+		}
+		return i+j+2;
+	}
+
+	static List<Long> find(long x){
+		List<Long> result = new ArrayList<>();
+
+		result.add(x);
+		while(x > 0) {
+			x = (x-1)/K;
+			result.add(x);
+		}
+		return result;
+	}
+
+}
+
+```