Package g2901_3000.s2940_find_building_where_alice_and_bob_can_meet

Class Solution

java.lang.Object
g2901_3000.s2940_find_building_where_alice_and_bob_can_meet.Solution
public class Solution extends java.lang.Object
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 ith 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 queries[i] = [ai, bi]. On the ith query, Alice is in building ai while Bob is in building bi.

Return an array ans where ans[i] is the index of the leftmost building where Alice and Bob can meet on the ith 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 heights[0] < heights[2] and heights[1] < heights[2].

In the second query, Alice and Bob can move to building 5 since heights[0] < heights[5] and heights[3] < heights[5].

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 heights[3] < heights[5] and heights[4] < heights[5].

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

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

For ans[i] == -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 heights[0] < heights[7].

In the second query, Alice and Bob can move to building 6 since heights[3] < heights[6] and heights[5] < heights[6].

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 heights[3] < heights[4] and heights[0] < heights[4].

In the fifth query, Alice can directly move to Bob’s building since heights[1] < heights[6].

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

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

Constraints:

  • 1 <= heights.length <= 5 * 104
  • 1 <= heights[i] <= 109
  • 1 <= queries.length <= 5 * 104
  • queries[i] = [ai, bi]
  • 0 <= ai, bi <= heights.length - 1

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int[]
    leftmostBuildingQueries(int[] heights, int[][] queries)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • leftmostBuildingQueries

      public int[] leftmostBuildingQueries(int[] heights, int[][] queries)