solution.java

class Solution {
    public int[][] highestPeak(int[][] isWater) {
        int m = isWater.length, n = isWater[0].length;
        int[][] height = new int[m][n];
        Queue<int[]> queue = new LinkedList<>();

        // Initialize heights and queue
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (isWater[i][j] == 1) {
                    height[i][j] = 0;
                    queue.offer(new int[] { i, j });
                } else {
                    height[i][j] = -1;
                }
            }
        }

        // Directions for BFS
        int[][] directions = { { 0, 1 }, { 0, -1 }, { 1, 0 }, { -1, 0 } };

        // BFS
        while (!queue.isEmpty()) {
            int[] cell = queue.poll();
            int x = cell[0], y = cell[1];
            for (int[] dir : directions) {
                int nx = x + dir[0], ny = y + dir[1];
                if (nx >= 0 && ny >= 0 && nx < m && ny < n && height[nx][ny] == -1) {
                    height[nx][ny] = height[x][y] + 1;
                    queue.offer(new int[] { nx, ny });
                }
            }
        }

        return height;
    }
}