1102. Path With Maximum Minimum Value

Given a matrix of integers ​​A​​ with R rows and C columns, find the maximum score of a path starting at ​​[0,0]​​ and ending at ​​[R-1,C-1]​​.

The score of a path is the minimum value in that path.  For example, the value of the path 8 →  4 →  5 →  9 is 4.

A path moves some number of times from one visited cell to any neighbouring unvisited cell in one of the 4 cardinal directions (north, east, west, south).

 

Example 1:

Input: [[5,4,5],[1,2,6],[7,4,6]]
Output: 4
Explanation: 
The path with the maximum score is highlighted in yellow.

Example 2:

Input: [[2,2,1,2,2,2],[1,2,2,2,1,2]]
Output: 2

Example 3:

Input: [[3,4,6,3,4],[0,2,1,1,7],[8,8,3,2,7],[3,2,4,9,8],[4,1,2,0,0],[4,6,5,4,3]]
Output: 3

1 class Solution {
 2     public int maximumMinimumPath(int[][] A) {
 3         int[][] DIRS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
 4         int n = A.length, m = A[0].length;
 5         Queue<int[]> pq = new PriorityQueue<>((a, b) -> Integer.compare(b[0], a[0]));
 6         pq.offer(new int[] { A[0][0], 0, 0 });
 7         int maxscore = A[0][0];
 8         A[0][0] = -1; // visited
 9         while (!pq.isEmpty()) {
10             int[] top = pq.poll();
11             maxscore = Math.min(maxscore, top[0]);
12             if (top[1] == n - 1 && top[2] == m - 1)
13                 break;
14             for (int[] d : DIRS) {
15                 int newi = d[0] + top[1], newj = d[1] + top[2];
16                 if (newi >= 0 && newi < n && newj >= 0 && newj < m && A[newi][newj] >= 0) {
17                     pq.offer(new int[] { A[newi][newj], newi, newj });
18                     A[newi][newj] = -1;
19                 }
20             }
21         }
22         return maxscore;
23     }
24 }