Solving the printing time puzzle on a circular printer. ๐Ÿš€๐Ÿ„๐Ÿช

Solving the printing time puzzle on a circular printer. ๐Ÿš€๐Ÿ„๐Ÿช

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3 min read

The question involves calculating the time taken to print a given string, where each character is located on a directionless printer and the pointer moves from one character to another in one second.

With the input string "AZGB", the index of 'A' is 0, the index of 'Z' is 25, the index of 'G' is 6, and the index of 'B' is 1. The total time required to print the string is 1 + 7 + 5 = 13.

Here's a step-by-step explanation of the calculateTime function:

javascriptCopy codefunction calculateTime(input) {
  let time = 0;
  let prevIndex = 0;
  for (let i = 0; i < input.length; i++) {
    const currIndex = input.charCodeAt(i) - 'A'.charCodeAt(0);
    const diff = Math.min(
      Math.abs(currIndex - prevIndex),
      26 - Math.abs(currIndex - prevIndex)
    );
    time += diff;
    prevIndex = currIndex;
  }
  return time;
}

// Example usage
const input = "AZGB";
const totalTime = calculateTime(input);
console.log(totalTime); // Output: 13

In this implementation, Let's break down the above code step by step:

  1. The calculateTime function takes a single parameter input, which is the string that we want to calculate the printing time for.

  2. We initialize a variable time to keep track of the total time taken to print the string.

  3. We initialize prevIndex to 0, as the pointer starts at the letter A.

  4. We loop through each character in the input string using a for loop.

  5. Inside the loop, we calculate the index of the current character using the charCodeAt method, which returns the ASCII code of the character. We subtract the ASCII code of 'A' to get the index of the character in the alphabet.

  6. We calculate the absolute difference between the current index and the previous index using the abs function.

  7. We also calculate the absolute difference between the current index and the previous index if we were to go in the other direction. To do this, we subtract the absolute difference from 26, which is the number of letters in the alphabet.

  8. We take the minimum of the two differences using the min function. This ensures that we choose the shortest path to move the pointer from the previous character to the current character.

  9. We add the minimum difference to the time variable to keep track of the total time taken to print the string.

  10. We update the prevIndex variable to be the current index, so that we can use it to calculate the difference for the next character.

  11. Once the loop is complete, we return the time variable, which contains the total time taken to print the string.

  12. In the example usage, we define an input string "AZGB" and pass it to the calculateTime function. We store the return value in a variable totalTime.

  13. Finally, we print the value of totalTime to the console using the console.log function. This should output the value 13, which is the correct printing time for the input string "AZGB".

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