#536 · #1642 · Furthest Building You Can Reach(可以到达的最远建筑)

You are given heights of buildings, bricks and ladders. Moving from building i to i + 1 requires the height difference in bricks, or one ladder (usable regardless of the difference). Return the furthest building index reachable. Constraints: 1 <= heights.length <= 10^5, 0 <= bricks <= 10^9, 0 <= ladders <= heights.length.