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1102.Path-With-Maximum-Minimum-Value

1102. Path With Maximum Minimum Value

题目地址

题目描述

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).

代码

Approach #1 Priority BFS Greedy

class Solution {
int [][] dirs = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}};
public int maximumMinimumPath(int[][] A) {
int m = A.length;
int n = A[0].length;
PriorityQueue<int[]> maxHeap = new PriorityQueue<int[]>((a, b) -> b[2] - a[2]);
maxHeap.add(new int[]{0, 0, A[0][0]});
boolean [][] visited = new boolean[m][n];
visited[0][0] = true;
int res = A[0][0];
while (!maxHeap.isEmpty()) {
int[] cur = maxHeap.poll();
res = Math.min(res, cur[2]);
if (cur[0] == m - 1 && cur[1] == n - 1) {
return res;
}
for (int [] dir : dirs) {
int x = cur[0] + dir[0];
int y = cur[1] + dir[1];
if (x < 0 || x >= m || y < 0 || y >= n || visited[x][y]) {
continue;
}
visited[x][y] = true;
maxHeap.add(new int[]{x, y, A[x][y]});
}
}
return res;
}
}