Split List in C++

Suppose we have a list of integers called nums, we have to find whether we can partition the list into two sublists (non-empty) such that every number in the left part is strictly less than every number in the right part.

So, if the input is like [6,4,3,8,10], then the output will be true, as left = [6,4,3] and right = [8,10]

To solve this, we will follow these steps −

• n := size of nums

• Define an array right of size n

• Define an array left of size n

• left[0] := nums[0]

• last element of right := last element of nums

• for initialize i := 1, when i < n, update (increase i by 1), do −

  • left[i] := maximum of left[i - 1] and nums[i]

• for initialize i := n - 2, when i >= 0, update (decrease i by 1), do −

  • right[i] := minimum of right[i + 1] and nums[i]

• for initialize i := 0, when i < n - 1, update (increase i by 1), do −

  • if left[i] < right[i + 1], then −

    • return true

• return 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 n = nums.size();
      vector<int> right(n);
      vector<int> left(n);
      left[0] = nums[0];
      right.back() = nums.back();
      for (int i = 1; i < n; i++) {
         left[i] = max(left[i - 1], nums[i]);
      }
      for (int i = n - 2; i >= 0; i--) {
         right[i] = min(right[i + 1], nums[i]);
      }
      for (int i = 0; i < n - 1; i++) {
         if (left[i] < right[i + 1])
         return true;
      }
      return false;
   }
};
main() {
   Solution ob;
   vector<int> v = {6,4,3,8,10};
   cout << (ob.solve(v));
}

Input

{6,4,3,8,10}

Output

1