没看视频， 开始做本题， 数据过了17/20， 犯了一个错误， 就是bfs 时， 当不是山峰，也不是山谷的时候， 不能直接return， 需要把剩下的高度相同的地方遍历完。

import java.io.*;
import java.util.*;
class Main{
    static BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
    static int N = 1010, row, col;
    static int[][] a = new int[N][N];
    static boolean[][] st = new boolean[N][N];
    static boolean hasHigher = false, hasLower = false;
    static int[][] dir = new int[][]{
        {-1, 0}, {-1, 1}, {0, 1}, {1, 1},
        {1, 0}, {1, -1}, {0, -1}, {-1, -1}};
    public static void main(String[] args) throws Exception{
        int n = Integer.valueOf(read.readLine());
        row = col = n;
        for(int i = 0; i < n; i++){
            String[] ss = read.readLine().split(" ");    
            for(int j = 0; j < n; j++){
                a[i][j] = Integer.valueOf(ss[j]);
            }
        }
        int peak = 0, vally = 0;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < n; j++){
                if(!st[i][j]){
                    hasHigher = false; hasLower = false;
                    bfs(i, j);
                    if(!hasHigher) peak++;
                    if(!hasLower) vally++;
                }
            }
        }
        System.out.println(peak + " " + vally);
    }

    public static void bfs(int x, int y){
        Queue<Integer> q = new LinkedList();
        int ref = reflect(x, y);
        int curNum = a[x][y];
        q.offer(ref);
        st[x][y] = true;
        while(!q.isEmpty()){
            int poll = q.poll();
            int[] def = deflect(poll);
            for(int i = 0; i < 8; i++){
                int nx = def[0] + dir[i][0];
                int ny = def[1] + dir[i][1];
                if(nx < 0 || nx >= row || ny < 0 || ny >= col)  continue;
                if(a[nx][ny] != curNum){
                    if(a[nx][ny] > curNum)  hasHigher = true;
                    else hasLower = true;
                }else if(!st[nx][ny]) {
                    st[nx][ny] = true;
                    ref = reflect(nx, ny);
                    q.offer(ref);
                }

            }

        }
    }

    public static int reflect(int x, int y){
        return x * col + y;
    }

    public static int[] deflect(int a){
        return new int[]{a / col, a % col};
    }
}