Problem
Given a 0-indexed integer array nums, return true **if it can be made *strictly increasing* after removing exactly one element, or false otherwise. If the array is already strictly increasing, return **true.
The array nums is strictly increasing if nums[i - 1] < nums[i] for each index (1 <= i < nums.length).
Example 1:
Input: nums = [1,2,10,5,7]
Output: true
Explanation: By removing 10 at index 2 from nums, it becomes [1,2,5,7].
[1,2,5,7] is strictly increasing, so return true.
Example 2:
Input: nums = [2,3,1,2]
Output: false
Explanation:
[3,1,2] is the result of removing the element at index 0.
[2,1,2] is the result of removing the element at index 1.
[2,3,2] is the result of removing the element at index 2.
[2,3,1] is the result of removing the element at index 3.
No resulting array is strictly increasing, so return false.
Example 3:
Input: nums = [1,1,1]
Output: false
Explanation: The result of removing any element is [1,1].
[1,1] is not strictly increasing, so return false.
Constraints:
2 <= nums.length <= 10001 <= nums[i] <= 1000
Solution (Java)
class Solution {
public boolean canBeIncreasing(int[] nums) {
boolean removed = false;
for (int i = 1; i < nums.length; i++) {
if (nums[i] <= nums[i - 1]) {
if (removed) {
return false;
} else {
removed = true;
}
if (i > 1 && nums[i] <= nums[i - 2]) {
nums[i] = nums[i - 1];
}
}
}
return true;
}
}
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).