skiing

 package noj_skiing;

 import java.util.*;
 import java.math.*;

 public class Main {

     public static void main(String[] args) {
         Solution s = new Solution();
         Scanner sc = new Scanner(System.in);
         int N = sc.nextInt();
         int[] result = new int[N];
         for(int i = 0; i < N; i++) {
             int rowNum = sc.nextInt();
             int colNum = sc.nextInt();
             int[][] info = new int[rowNum][colNum];
             for(int r = 0; r < rowNum; r++) {
                 for(int c = 0; c < colNum; c++) {
                     info[r][c] = sc.nextInt();
                 }
             }
             result[i] = s.getResult(info, rowNum, colNum);
         }
         sc.close();
         for(int i : result) {
             System.out.println(i);
         }
     }

 }
 class Solution {
     public int getResult(int[][] info, int rowNum, int colNum) {
         int max = 0;
         int[][] states = new int[rowNum][colNum]; //make sure equal 0 all
         for(int r = 0; r < rowNum; r++) {
             for(int c = 0; c < colNum; c++) {
                 max = Math.max(max, getMaxLength(info, r, c, rowNum, colNum, states));
             }
         }
         return max;
     }
     public int getMaxLength(int[][] info, int row, int col, int rowNum, int colNum, int[][] states) {

         if(row < 0 || row >= rowNum || col < 0 || col >= colNum) //如果输入的坐标越界的处理
             return 0;
         if(states[row][col] != 0) //所求位置的最大长度求过
             return states[row][col];

         int nextStep = findNextStep(info, row, col, rowNum, colNum);
         if(nextStep == 0) //所求位置在队尾
             return states[row][col] = 1;
         int maxLengthUp     = (nextStep & 8) == 8 ? getMaxLength(info, row - 1, col, rowNum, colNum, states) : 0;
         int maxLengthDown     = (nextStep & 4) == 4 ? getMaxLength(info, row + 1, col, rowNum, colNum, states) : 0;
         int maxLengthLeft     = (nextStep & 2) == 2 ? getMaxLength(info, row, col - 1, rowNum, colNum, states) : 0;
         int maxLengthRight     = (nextStep & 1) == 1 ? getMaxLength(info, row, col + 1, rowNum, colNum, states) : 0;

         return max_4(maxLengthUp, maxLengthDown, maxLengthLeft, maxLengthRight) + 1;
     }
     public int findNextStep(int[][] info, int row, int col, int rowNum, int colNum) {
         int result = 0;

         if(row != 0 && info[row - 1][col] < info[row][col])             //up
             result |= 8;
         if(row != rowNum - 1 && info[row + 1][col] < info[row][col])     //down
             result |= 4;
         if(col != 0 && info[row][col - 1] < info[row][col])             //left
             result |= 2;
         if(col != colNum - 1 && info[row][col + 1] < info[row][col])     //right
             result |= 1;

         return result;
     }
     public int max_4(int i_1, int i_2, int i_3, int i_4) {
         return Math.max(Math.max(i_1, i_2), Math.max(i_3, i_4));
     }
 }

感觉不是很难，思路一上来就可以想出来，具体一些细节的处理也没有很坑的地方。