994. Rotting Oranges

https://leetcode.com/problems/rotting-oranges/description/

LeetCode - The World's Leading Online Programming Learning Platform

 

class Solution {
    public int orangesRotting(int[][] grid) {
        Queue<int[]> queue = new LinkedList<>();
        int total = 0;
        for(int i = 0; i < grid.length; i++) {
            for(int j = 0; j < grid[i].length; j++) {
                if (grid[i][j] == 2) {
                    total += 1;
                    queue.add(new int[]{i, j});
                }
                if (grid[i][j] == 1) {
                    total += 1;
                }
            }
        }

        int rotten = 0, minute = 0;
        while(true) {
            Queue<int[]> temp = new LinkedList<>(queue);
            
            rotten = 0;
            while(!temp.isEmpty()) {
                int[] curr = temp.poll();
                
                if (curr[0] - 1 >= 0 && grid[curr[0] - 1][curr[1]] == 1) {
                    rotten += 1;
                    grid[curr[0] - 1][curr[1]] = 2;
                    queue.add(new int[]{curr[0] - 1, curr[1]});
                }
                if (curr[1] - 1 >= 0 && grid[curr[0]][curr[1] - 1] == 1) {
                    rotten += 1;
                    grid[curr[0]][curr[1] - 1] = 2;
                    queue.add(new int[]{curr[0], curr[1] - 1});
                }
                if (curr[0] + 1 < grid.length && grid[curr[0] + 1][curr[1]] == 1) {
                    rotten += 1;
                    grid[curr[0] + 1][curr[1]] = 2;
                    queue.add(new int[]{curr[0] + 1, curr[1]});
                }
                if (curr[1] + 1 < grid[0].length && grid[curr[0]][curr[1] + 1] == 1) {
                    rotten += 1;
                    grid[curr[0]][curr[1] + 1] = 2;
                    queue.add(new int[]{curr[0], curr[1] + 1});
                }
            }


            if (rotten == 0) {
                break;
            }
            minute++;
        }

        if (queue.size() == total) {
            return minute;
        }
        return -1;
    }
}