LeetCode/java/path-with-maximum-gold.java

class Solution {
  private int dfs(int[][] grid, int x, int y) {
    int rows = grid.length;
    int cols = grid[0].length;

    // BASE: out of bounds
    if (y < 0 || y >= rows || x < 0 || x >= cols) {
      return 0;
    }

    // BASE: nothing to collect
    if (grid[y][x] == 0) {
      return 0;
    }

    int found = 0;

    int current = grid[y][x];

    grid[y][x] = 0;
    for (int d = -1; d <= 1; d += 2) {
      found = Math.max(found, dfs(grid, x + d, y));
      found = Math.max(found, dfs(grid, x, y + d));
    }
    grid[y][x] = current;

    return found + current;
  }

  public int getMaximumGold(int[][] grid) {
    int rows = grid.length;
    int cols = grid[0].length;

    int maxGoldFound = 0;
    for (int i = 0; i < rows * cols; ++i) {
      int y = i / cols;
      int x = i % cols;

      maxGoldFound = Math.max(maxGoldFound, dfs(grid, x, y));
    }

    return maxGoldFound;
  }
}