Here, We see Split Array into Consecutive Subsequences LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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Split Array into Consecutive Subsequences LeetCode Solution

Problem Statement

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 3 or 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.

Split Array into Consecutive Subsequences LeetCode Solution C++

class Solution {
public:
    bool isPossible(vector<int>& nums) {
        unordered_map<int,int> mp;
        for(auto& it:nums)
            mp[it]++;
        for(auto& it:nums)
        {
            if(mp[it] == 0)
                continue;
            int freq = mp[it] , curr = it , count = 0;
            while(mp.count(curr) && mp[curr] >= freq)
            {
                freq = fmax(freq,mp[curr]);
                mp[curr]--;
                count++;
                curr++;
            }
            if(count < 3)
                return false;
        }
        return true;
    }
};Code language: PHP (php)

Split Array into Consecutive Subsequences LeetCode Solution Java

class Solution {
    public boolean isPossible(int[] nums) {
        HashMap<Integer,Integer> avaibilityMap = new HashMap<>();
        HashMap<Integer,Integer> wantMap = new HashMap<>();
        for(int i : nums){
            avaibilityMap.put(i, avaibilityMap.getOrDefault(i,0)+1);
        }
        for(int i=0;i<nums.length;i++){
            if(avaibilityMap.get(nums[i])<=0){
                continue;
            }
            else if(wantMap.getOrDefault(nums[i],0)>0){
                avaibilityMap.put(nums[i], avaibilityMap.getOrDefault(nums[i],0)-1);
                wantMap.put(nums[i], wantMap.getOrDefault(nums[i],0)-1);
                wantMap.put(nums[i]+1, wantMap.getOrDefault(nums[i]+1,0)+1);
            }
            else if(avaibilityMap.getOrDefault(nums[i],0)>0 && avaibilityMap.getOrDefault(nums[i]+1,0)>0 && avaibilityMap.getOrDefault(nums[i]+2,0)>0){
                avaibilityMap.put(nums[i], avaibilityMap.getOrDefault(nums[i],0)-1);
                avaibilityMap.put(nums[i]+1, avaibilityMap.getOrDefault(nums[i]+1,0)-1);
                avaibilityMap.put(nums[i]+2, avaibilityMap.getOrDefault(nums[i]+2,0)-1);
                wantMap.put(nums[i]+3, wantMap.getOrDefault(nums[i]+3,0)+1);
            }
            else{
                return false;
            }
        }
        return true;
    }
}Code language: PHP (php)

Split Array into Consecutive Subsequences Solution JavaScript

var isPossible = function(nums) {
    if(nums.length < 3) return false;
    const freqMap = new Map(), appendfreq = new Map();
    nums.forEach(card => {
        if (!freqMap.has(card))
            freqMap.set(card, 0);
        
        freqMap.set(card, freqMap.get(card) + 1);
    });
     for (let i of nums) {
        if (freqMap.get(i) == 0) continue;
        else if ((appendfreq.get(i) || 0) > 0) {
            appendfreq.set(i, appendfreq.get(i) - 1);
            appendfreq.set(i+1, (appendfreq.get(i+1) || 0) + 1);
        }   
        else if ((freqMap.get(i+1) || 0) > 0 && (freqMap.get(i+2) || 0) > 0) {
            freqMap.set(i+1, freqMap.get(i+1) - 1);
            freqMap.set(i+2, freqMap.get(i+2) - 1);
            appendfreq.set(i+3, (appendfreq.get(i+3) || 0) + 1);
        }
        else return false;
        freqMap.set(i, freqMap.get(i) - 1);
    }
    return true;
};Code language: JavaScript (javascript)

Split Array into Consecutive Subsequences Solution Python

class Solution(object):
    def isPossible(self, nums):
        seq = defaultdict(int)
        left = Counter(nums)
        for num in nums:
            if (not left[num]): continue
            if (seq[num-1] > 0):
                seq[num-1] -= 1 
                seq[num] += 1
                left[num] -= 1
            else:
                if (not left[num+1] or not left[num+2]):
                    return False
                left[num] -= 1
                left[num+1] -= 1
                left[num+2] -= 1
                seq[num+2] += 1
        return True