Typescript Coding Chronicles: Kids With the Greatest Number of Candies
Tags: webdev, javascript, programming, typescript
Published: 2024-07-10 19:44:16

## Problem Statement:
There are `n` kids with candies. You are given an integer array `candies`, where each `candies[i]` represents the number of candies the `i`-th kid has, and an integer `extraCandies`, denoting the number of extra candies that you have.

Return a boolean array `result` of length `n`, where `result[i]` is `true` if, after giving the `i`-th kid all the `extraCandies`, they will have the greatest number of candies among all the kids, or `false` otherwise.

Note that multiple kids can have the greatest number of candies.

### Example 1:
- Input: `candies = [2,3,5,1,3]`, `extraCandies = 3`
- Output: `[true,true,true,false,true]`
- Explanation:
  - Kid 1: 2 + 3 = 5 candies, which is the greatest among the kids.
  - Kid 2: 3 + 3 = 6 candies, which is the greatest among the kids.
  - Kid 3: 5 + 3 = 8 candies, which is the greatest among the kids.
  - Kid 4: 1 + 3 = 4 candies, which is not the greatest among the kids.
  - Kid 5: 3 + 3 = 6 candies, which is the greatest among the kids.

### Example 2:
- Input: `candies = [4,2,1,1,2]`, `extraCandies = 1`
- Output: `[true,false,false,false,false]`
- Explanation:
  - Kid 1 will always have the greatest number of candies, even if a different kid is given the extra candy.

### Example 3:
- Input: `candies = [12,1,12]`, `extraCandies = 10`
- Output: `[true,false,true]`

### Constraints:
- `n == candies.length`
- `2 <= n <= 100`
- `1 <= candies[i] <= 100`
- `1 <= extraCandies <= 50`

## Initial Thought Process:
The basic approach is to:
1. Find the maximum number of candies that any kid currently has.
2. Iterate through each kid, and check if giving them all the `extraCandies` makes their total candies greater than or equal to the current maximum number of candies.
3. Return a boolean array where each element indicates whether that kid can have the greatest number of candies.

## Basic Solution:
### Code:
```typescript
function kidsWithCandiesBasic(candies: number[], extraCandies: number): boolean[] {
    let maxCandies = Math.max(...candies);
    let result: boolean[] = [];

    for (let i = 0; i < candies.length; i++) {
        if (candies[i] + extraCandies >= maxCandies) {
            result.push(true);
        } else {
            result.push(false);
        }
    }

    return result;
}
```

### Time Complexity Analysis:
- **Time Complexity:** O(n), where n is the number of kids. Finding the maximum candies takes O(n), and iterating through the candies array also takes O(n).
- **Space Complexity:** O(n), for the result array of boolean values.

### Limitations:
This solution is efficient given the constraints. It works within the allowed time and space complexities.

## Optimized Solution:
The basic solution is already optimal in terms of time complexity. However, we can focus on making the code more concise and clean.

### Code:
```typescript
function kidsWithCandiesOptimized(candies: number[], extraCandies: number): boolean[] {
    const maxCandies = Math.max(...candies);
    return candies.map(candy => candy + extraCandies >= maxCandies);
}
```

### Time Complexity Analysis:
- **Time Complexity:** O(n), where n is the number of kids. Finding the maximum candies takes O(n), and mapping through the candies array also takes O(n).
- **Space Complexity:** O(n), for the result array of boolean values.

### Improvements Over Basic Solution:
- The optimized solution uses `Array.prototype.map`, which makes the code more concise and readable.

## Edge Cases and Testing:
### Edge Cases:
1. `candies` array has minimum and maximum values.
2. `extraCandies` is equal to the number of candies the kid with the most candies has.
3. `extraCandies` is much smaller than the number of candies the kid with the most candies has.

### Test Cases:
```typescript
console.log(kidsWithCandiesBasic([2,3,5,1,3], 3)); // [true, true, true, false, true]
console.log(kidsWithCandiesBasic([4,2,1,1,2], 1)); // [true, false, false, false, false]
console.log(kidsWithCandiesBasic([12,1,12], 10)); // [true, false, true]

console.log(kidsWithCandiesOptimized([2,3,5,1,3], 3)); // [true, true, true, false, true]
console.log(kidsWithCandiesOptimized([4,2,1,1,2], 1)); // [true, false, false, false, false]
console.log(kidsWithCandiesOptimized([12,1,12], 10)); // [true, false, true]
```

## General Problem-Solving Strategies:
1. **Understand the Problem:** Carefully read the problem statement and constraints to understand what is required.
2. **Identify Key Operations:** Determine the key operations needed, such as finding the maximum value and iterating through the array.
3. **Optimize for Readability:** Use built-in functions like `Math.max` and `Array.prototype.map` to make the code concise and readable.
4. **Test Thoroughly:** Test the solution with various cases, including edge cases, to ensure correctness.

## Identifying Similar Problems:
1. **Finding the Maximum Element:**
   - Problems where you need to determine the maximum element in an array.
   - Example: Finding the maximum score in a game leaderboard.

2. **Conditional Array Mapping:**
   - Problems where you need to create a new array based on a condition applied to each element of the original array.
   - Example: Creating an array of booleans indicating whether students passed based on their scores.

3. **Comparison with Extra Values:**
   - Problems where you need to compare elements of an array with an additional value to determine a condition.
   - Example: Checking if adding a bonus to employees' scores makes them eligible for a reward.

## Conclusion:
- The problem of determining if kids can have the greatest number of candies after adding extra candies can be efficiently solved using a straightforward approach.
- Understanding the problem and breaking it down into manageable parts is crucial.
- Using built-in functions can make the code more concise and readable.
- Testing with various edge cases ensures robustness.
- Recognizing patterns in problems can help apply similar solutions to other challenges.

By practicing such problems and strategies, you can improve your problem-solving skills and be better prepared for various coding challenges.