视频中标准程序代码如下： ```java import java.util.*; class Main { static final int N = 1005; static List<Integer>[] G = new ArrayList[N]; static List<Integer>[][] dp = new ArrayList[N][N]; static double[][] f = new double[N][N]; static double ans = 0; static int[] vis = new int[N]; static class Node { int x, y; Node(int x, int y) { this.x = x; this.y = y; } } static void bfs(int rt) { Arrays.fill(vis, 0); vis[rt] = 1; Queue<Node> q = new LinkedList<>(); q.add(new Node(rt, 0)); while (!q.isEmpty()) { Node p = q.poll(); dp[rt][p.y].add(p.x); for (int it : G[p.x]) { if (vis[it] == 0) { vis[it] = 1; q.add(new Node(it, p.y + 1)); } } } } public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int n = scanner.nextInt(); int m = scanner.nextInt(); int q = scanner.nextInt(); for (int i = 1; i <= n; i++) { G[i] = new ArrayList<>(); for (int j = 0; j <= n; j++) { dp[i][j] = new ArrayList<>(); } } for (int i = 1; i <= m; i++) { int x = scanner.nextInt(); int y = scanner.nextInt(); G[x].add(y); G[y].add(x); } for (int i = 1; i <= n; i++) { Arrays.fill(vis, 0); vis[i] = 1; bfs(i); } for (int i = 1; i <= n; i++) { for (int j = 0; j <= n; j++) { if (j == 0) f[i][j] = dp[i][0].size(); else f[i][j] = f[i][j - 1] + dp[i][j].size(); } } for (int i = 1; i <= q; i++) { int x = scanner.nextInt(); int y = scanner.nextInt(); ans += f[x][y]; } System.out.printf("%.2f", ans / q); } } ```