2940 - Find Building Where Alice and Bob Can Meet.

Hard

You are given a 0-indexed array heights of positive integers, where heights[i] represents the height of the <code>i^th</code> building.

If a person is in building i, they can move to any other building j if and only if i < j and heights[i] < heights[j].

You are also given another array queries where <code>queriesi = a_i, b_i</code>. On the <code>i^th</code> query, Alice is in building <code>a_i</code> while Bob is in building <code>b_i</code>.

Return an array ans where ans[i] is the index of the leftmost building where Alice and Bob can meet on the <code>i^th</code> query. If Alice and Bob cannot move to a common building on query i, set ans[i] to -1.

Example 1:

Input: heights = 6,4,8,5,2,7, queries = \[\[0,1],0,3,2,4,3,4,2,2]

Output: 2,5,-1,5,2

Explanation: In the first query, Alice and Bob can move to building 2 since heights0< heights2 and heights1< heights2.

In the second query, Alice and Bob can move to building 5 since heights0< heights5 and heights3< heights5.

In the third query, Alice cannot meet Bob since Alice cannot move to any other building.

In the fourth query, Alice and Bob can move to building 5 since heights3< heights5 and heights4< heights5.

In the fifth query, Alice and Bob are already in the same building.

For ansi != -1, It can be shown that ansi is the leftmost building where Alice and Bob can meet.

For ansi == -1, It can be shown that there is no building where Alice and Bob can meet.

Example 2:

Input: heights = 5,3,8,2,6,1,4,6, queries = \[\[0,7],3,5,5,2,3,0,1,6]

Output: 7,6,-1,4,6

Explanation: In the first query, Alice can directly move to Bob's building since heights0< heights7.

In the second query, Alice and Bob can move to building 6 since heights3< heights6 and heights5< heights6.

In the third query, Alice cannot meet Bob since Bob cannot move to any other building.

In the fourth query, Alice and Bob can move to building 4 since heights3< heights4 and heights0< heights4.

In the fifth query, Alice can directly move to Bob's building since heights1< heights6.

For ansi != -1, It can be shown that ansi is the leftmost building where Alice and Bob can meet.

For ansi == -1, It can be shown that there is no building where Alice and Bob can meet.

Constraints:

• <code>1 <= heights.length <= 5 * 10⁴</code>

• <code>1 <= heightsi<= 10⁹</code>

• <code>1 <= queries.length <= 5 * 10⁴</code>

• <code>queriesi = a_i, b_i</code>

• <code>0 <= a_i, b_i<= heights.length - 1</code>