There is a 1 million by 1 million grid on an XY-plane, and the coordinates of each grid square are
We start at the
source = [sx, sy] square and want to reach the
target = [tx, ty] square. There is also an array of
blocked squares, where each
blocked[i] = [xi, yi] represents a blocked square with coordinates
Each move, we can walk one square north, east, south, or west if the square is not in the array of
blocked squares. We are also not allowed to walk outside of the grid.
true if and only if it is possible to reach the
target square from the
source square through a sequence of valid moves.
Input: blocked = [[0,1],[1,0]], source = [0,0], target = [0,2] Output: false Explanation: The target square is inaccessible starting from the source square because we cannot move. We cannot move north or east because those squares are blocked. We cannot move south or west because we cannot go outside of the grid.
Input: blocked = , source = [0,0], target = [999999,999999] Output: true Explanation: Because there are no blocked cells, it is possible to reach the target square.
0 <= blocked.length <= 200
blocked[i].length == 2
0 <= xi, yi < 106
source.length == target.length == 2
0 <= sx, sy, tx, ty < 106
source != target
targetare not blocked.