Program to check whether list can be split into sublists of k increasing elements in C++

Suppose we have a list of numbers called nums, and another number k, we have to check whether the list can be split into lists where each list contains k values and the values are consecutively increasing.

So, if the input is like nums = [4, 3, 2, 4, 5, 6], k = 3, then the output will be True, as we can split the list into [2, 3, 4] and [4, 5, 6]

To solve this, we will follow these steps −

• Define one map

• for each key it in m

  • increase m[it] by 1

• ok := true

• while (size of m is not 0 and ok is true), do −

  • ok := false

  • for each key-value pair it in m

    • if (it.key - 1) is not in m, then −

      • flag := true

      • for initialize i := it.key, when i <= it.key + k - 1, update (increase i by 1), do −

        • if i is not present in m, then −

          • flag := false

      • if flag is true, then −

        • for initialize i := it.key , when i <= it.key + k - 1, update (increase i by 1), do −

          • (decrease m[i] by 1)

          • if m[i] is same as 0, then −

            • delete i from m

        • ok := true

        • Come out from the loop

• return true when m is empty, otherwise false.

Let us see the following implementation to get better understanding −

Example

 Live Demo

#include<bits/stdc++.h>
using namespace std;
class Solution {
   public:
      bool solve(vector<int> nums, int k) {
         map <int, int> m;
         for(auto& it : nums){
            m[it]++;
         }
         bool ok = true;
         while(m.size() && ok){
            ok = false;
            for(auto& it : m){
               if(!m.count(it.first - 1)){
                  bool flag = true;
                  for(int i = it.first; i <= it.first + k - 1;i++){
                     if(!m.count(i))
                        flag = false;
                     }
                     if(flag){
                        for(int i = it.first; i <= it.first + k - 1;i++){
                           m[i]--;
                           if(m[i] == 0)
                              m.erase(i);

                     }
                     ok = true;
                     break;
                  }
               }
            }
         }
         return m.empty();
      }
};
main(){
   vector<int> v = {4, 3, 2, 4, 5, 6};
   Solution ob;
   cout << ob.solve(v, 3);
}

Input

{4, 3, 2, 4, 5, 6}

Output

1