Skip to content

Latest commit

 

History

History
123 lines (81 loc) · 5.63 KB

explanation.md

File metadata and controls

123 lines (81 loc) · 5.63 KB
Raw

Divide Players Solution: Step-by-Step Explanation for Multiple Languages

This guide will walk through the solution to the problem of dividing players into pairs based on their skills, calculating the total "chemistry" between these pairs. We'll cover the logic in C++, Java, JavaScript, Python, and Go. Each explanation follows the same structure, but is adapted to the syntax and characteristics of the respective language.

Problem Breakdown

We are given an array of integers representing the skill levels of players. The goal is to divide the players into pairs such that the sum of skills in each pair is the same, and then calculate the total chemistry for valid configurations. Chemistry for each pair is calculated as the product of their skills.

The key steps are:

  1. Sort the array to make it easier to form pairs.
  2. Use two pointers to pair players from the beginning and the end of the sorted array.
  3. Validate the pair sum to ensure it matches the target sum.
  4. Calculate the total chemistry by summing the product of skills for each valid pair.

C++ Solution Explanation

  1. Step 1: Sort the skill array
    The first thing we do is sort the skill array. This allows us to easily form pairs with the first and last elements in the sorted array.

  2. Step 2: Define the required total skill
    After sorting, the sum of the first and last elements becomes the required skill sum for each pair.

  3. Step 3: Pair players using two pointers
    We iterate using a two-pointer technique, where one pointer starts from the beginning and the other from the end of the array. At each step, we:

    • Check if the sum of the current pair matches the required total.
    • If the sum doesn't match, we return -1 indicating an invalid configuration.

  4. Step 4: Calculate chemistry
    If the pair is valid, we compute the chemistry by multiplying the skills of the pair and adding it to a running total.

  5. Step 5: Return the total chemistry
    Finally, after all pairs are processed, return the total chemistry sum.

Java Solution Explanation

  1. Step 1: Sort the skill array
    The array is sorted using Arrays.sort(). Sorting helps ensure we can form pairs from both ends of the array.

  2. Step 2: Define the required total skill
    The total required skill sum is determined by adding the first and last elements of the sorted array.

  3. Step 3: Pair players using two pointers
    We loop through the array with one pointer starting at the beginning and another at the end:

    • Check if the sum of the current pair equals the required total skill.
    • If it doesn't match, return -1 to signal an invalid configuration.

  4. Step 4: Calculate chemistry
    For valid pairs, multiply their skills and accumulate the result.

  5. Step 5: Return the total chemistry
    After processing all pairs, the final chemistry sum is returned.

JavaScript Solution Explanation

  1. Step 1: Sort the skill array
    The sort() method is used to sort the array in ascending order. Sorting allows easier pairing of the players.

  2. Step 2: Define the required total skill
    The sum of the first and last elements in the sorted array gives the required skill sum for each pair.

  3. Step 3: Pair players using two pointers
    We use a loop where one pointer starts at the beginning and another at the end of the array. For each pair:

    • Check if the sum matches the required total skill.
    • If the sum doesn't match, return -1 as an invalid configuration.

  4. Step 4: Calculate chemistry
    For valid pairs, compute the product of their skills and add it to the total chemistry sum.

  5. Step 5: Return the total chemistry
    Once all pairs are processed, return the total chemistry.

Python Solution Explanation

  1. Step 1: Sort the skill array
    The array is sorted using the sort() function. Sorting simplifies the process of pairing players from opposite ends of the array.

  2. Step 2: Define the required total skill
    The total skill required for each pair is the sum of the first and last elements of the sorted array.

  3. Step 3: Pair players using two pointers
    Iterate over the first half of the array while pairing it with the second half (from the end to the start). For each pair:

    • Check if the sum of skills matches the required total.
    • If the sum doesn't match, return -1 to indicate an invalid configuration.

  4. Step 4: Calculate chemistry
    For valid pairs, compute the product of their skills and accumulate the result.

  5. Step 5: Return the total chemistry
    After processing all pairs, return the total chemistry sum.

Go Solution Explanation

  1. Step 1: Sort the skill array
    The sort.Ints() function sorts the array. Sorting helps us form pairs easily.

  2. Step 2: Define the required total skill
    The required skill sum is determined by adding the first and last elements of the sorted array.

  3. Step 3: Pair players using two pointers
    We loop through the array, pairing elements from the beginning and the end. For each pair:

    • Check if the sum matches the required total skill.
    • If the sum doesn't match, return -1.

  4. Step 4: Calculate chemistry
    For valid pairs, calculate the product of their skills and add it to the chemistry sum.

  5. Step 5: Return the total chemistry
    Once all pairs are processed, return the final chemistry sum.

Each solution follows the same logical flow with minor variations in syntax based on the language. By understanding this flow, you can easily adapt the solution to any language or problem with a similar structure.