LeetCode-in-Java
659. Split Array into Consecutive Subsequences
Medium
You are given an integer array nums that is sorted in non-decreasing order.
Determine if it is possible to split nums into one or more subsequences such that both of the following conditions are true:
- Each subsequence is a consecutive increasing sequence (i.e. each integer is exactly one more than the previous integer).
- All subsequences have a length of
3or more.
Return true if you can split nums according to the above conditions, or false otherwise.
A subsequence of an array is a new array that is formed from the original array by deleting some (can be none) of the elements without disturbing the relative positions of the remaining elements. (i.e., [1,3,5] is a subsequence of [1,2,3,4,5] while [1,3,2] is not).
Example 1:
Input: nums = [1,2,3,3,4,5]
Output: true
Explanation: nums can be split into the following subsequences:
[1,2,3,3,4,5] –> 1, 2, 3
[1,2,3,3,4,5] –> 3, 4, 5
Example 2:
Input: nums = [1,2,3,3,4,4,5,5]
Output: true
Explanation: nums can be split into the following subsequences:
[1,2,3,3,4,4,5,5] –> 1, 2, 3, 4, 5
[1,2,3,3,4,4,5,5] –> 3, 4, 5
Example 3:
Input: nums = [1,2,3,4,4,5]
Output: false
Explanation: It is impossible to split nums into consecutive increasing subsequences of length 3 or more.
Constraints:
1 <= nums.length <= 104-1000 <= nums[i] <= 1000numsis sorted in non-decreasing order.
Solution
public class Solution {
public boolean isPossible(int[] nums) {
int[] element = new int[2001];
for (int num : nums) {
element[num + 1000] += 1;
}
for (int i = 0; i < element.length; i++) {
while (element[i] > 0) {
int length = 1;
while (i + length < element.length
&& element[i + length] >= element[i + length - 1]) {
length += 1;
}
if (length < 3) {
return false;
} else {
for (int j = i; j < i + length; j++) {
element[j] -= 1;
}
}
}
}
return true;
}
}