Search in a Grid

Intro

A grid is essentially a lattice. The edges normally are undirected and have cost of 1. BFS normally gets the job done.

Auxiliary Functions

Define Position

private class Pos {
    int row;
    int col;
    public Pos(int row, int col) {
        this.row = row;
        this.col = col;
    }
}

Search Directions

int[] drow = new int[] {0, -1, 0, 1};
int[] dcol = new int[] {-1, 0, 1, 0};

Check inbound

private boolean inBound(char[][] grid, Pos pt) {
    int m = grid.length;
    int n = grid[0].length;
    if (pt.row < 0 || pt.row >= m) {
        return false;
    }
    if (pt.col < 0 || pt.col >= n) {
        return false;
    }
    return true;
}