摘要：
Given a 2D grid, each cell is either a wall 2, an house 1or empty 0 (the number zero, one, two), find a place to build a post office so that the sum o 阅读全文
摘要：
Given a 2D grid, each cell is either an house 1 or empty 0 (the number zero, one), find the place to build a post office, the distance that post offic 阅读全文
摘要：
Given a knight in a chessboard (a binary matrix with 0 as empty and 1 as barrier) with a source position, find the shortest path to a destination posi 阅读全文