You want to build n
new buildings in a city. The new buildings will be built in a line and are labeled from 1
to n
.
However, there are city restrictions on the heights of the new buildings:
- The height of each building must be a non-negative integer.
- The height of the first building must be
0
. - The height difference between any two adjacent buildings cannot exceed
1
.
Additionally, there are city restrictions on the maximum height of specific buildings. These restrictions are given as a 2D integer array restrictions
where restrictions[i] = [idi, maxHeighti]
indicates that building idi
must have a height less than or equal to maxHeighti
.
It is guaranteed that each building will appear at most once in restrictions
, and building 1
will not be in restrictions
.
Return the maximum possible height of the tallest building.
Example 1:
Input: n = 5, restrictions = [[2,1],[4,1]] Output: 2 Explanation: The green area in the image indicates the maximum allowed height for each building. We can build the buildings with heights [0,1,2,1,2], and the tallest building has a height of 2.
Example 2:
Input: n = 6, restrictions = [] Output: 5 Explanation: The green area in the image indicates the maximum allowed height for each building. We can build the buildings with heights [0,1,2,3,4,5], and the tallest building has a height of 5.
Example 3:
Input: n = 10, restrictions = [[5,3],[2,5],[7,4],[10,3]] Output: 5 Explanation: The green area in the image indicates the maximum allowed height for each building. We can build the buildings with heights [0,1,2,3,3,4,4,5,4,3], and the tallest building has a height of 5.
Constraints:
2 <= n <= 109
0 <= restrictions.length <= min(n - 1, 105)
2 <= idi <= n
idi
is unique.0 <= maxHeighti <= 109