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Problem · Hash Table

Maximum Number of Balls in a Box

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You are working in a ball factory where you have n balls numbered from lowLimit up to highLimit inclusive (i.e., n == highLimit - lowLimit + 1), and an infinite number of boxes numbered from 1 to infinity.

Your job is to put each ball in the box whose number equals the sum of the digits of the ball's number. For example, the ball numbered 321 goes in box 3 + 2 + 1 = 6, and the ball numbered 10 goes in box 1 + 0 = 1.

Given two integers lowLimit and highLimit, return the number of balls in the box with the most balls.

Examples
01 · Example 1
lowLimit = 1
highLimit = 10
return = 2
Box 1 receives both ball 1 (digit sum 1) and ball 10 (1+0=1), so the most-filled box has 2 balls.
02 · Example 2
lowLimit = 5
highLimit = 15
return = 2
Box 6 holds balls 6 and 15 (1+5=6); no other box has more than 1 ball.
03 · Example 3
lowLimit = 19
highLimit = 28
return = 2
Balls 19 (1+9=10) and 28 (2+8=10) both land in box 10; every other box has 1 ball.
Constraints
  • 1 <= lowLimit <= highLimit <= 10^5
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public int countBalls(int lowLimit, int highLimit) {
  // write your code here
}
lowLimit1
highLimit10
expected2
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