[20250616] BOJ / G3 / 역사 / 김수연

suyeun84/202506/16 BOJ G3 역사.md

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+```java
+import java.io.*;
+import java.util.*;
+
+public class boj1613 {
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static StringTokenizer st;
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+
+	static int N;
+	static int[][] floyd;
+	static int INF = 100000000;
+	public static void main(String[] args) throws Exception {
+		nextLine();
+		N = nextInt();
+		int K = nextInt();
+		floyd = new int[N+1][N+1];
+		for (int i = 0; i < N+1; i++) {
+			Arrays.fill(floyd[i], INF);
+			floyd[i][i] = 0;
+		}
+		for (int i = 0; i < K; i++) {
+			nextLine();
+			int a = nextInt();
+			int b = nextInt();
+			floyd[a][b] = 1;
+		}
+		solve();
+		nextLine();
+		int S = nextInt();
+		for (int i = 0; i < S; i++) {
+			nextLine();
+			int a = nextInt();
+			int b = nextInt();
+			if (floyd[a][b] != INF) System.out.println(-1);
+			else if (floyd[b][a] != INF) System.out.println(1);
+			else System.out.println(0);
+		}
+	}
+
+	static void solve() {
+		for (int k = 1; k <= N; k++) {
+			for (int i = 1; i <= N; i++) {
+				for (int j = 1; j <= N; j++) {
+					if (floyd[i][k] == INF || floyd[k][j] == INF) continue;
+					floyd[i][j] = Math.min(floyd[i][j], floyd[i][k]+floyd[k][j]);
+				}
+			}
+		}
+	}
+}
+```