Number of Visible People in a Queue

arraystackmonotonic stack

Problem Statement

There are n people standing in a queue, and they numbered from 0 to n - 1 in left to right order. You are given an array heights of distinct integers where heights[i] represents the height of the i ^th person.

A person can see another person to their right in the queue if everybody in between is shorter than both of them. More formally, the i ^th person can see the j ^th person if i < j and min(heights[i], heights[j]) > max(heights[i+1], heights[i+2], ..., heights[j-1]) .

Return an array answer of length n where answer[i] is the number of people the i ^th person can see to their right in the queue .

Examples

Example 1

Input: heights = [10,6,8,5,11,9]
Output: [3,1,2,1,1,0]
Person 0 can see person 1, 2, and 4.
Person 1 can see person 2.
Person 2 can see person 3 and 4.
Person 3 can see person 4.
Person 4 can see person 5.
Person 5 can see no one since nobody is to the right of them.

Example 2

Input: heights = [5,1,2,3,10]
Output: [4,1,1,1,0]

Constraints

n == heights.length

1 <= n <= 10 ^5

1 <= heights[i] <= 10 ^5

All the values of heights are unique .

😤

Hard

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicStack