修复joinSlots函数报错及时间时段合并逻辑问题求助

Let's break down the issues in your current code and fix them step by step:

Key Problems in the Original Code #

1. Array Out-of-Bounds Access:
   • Your loop uses i<=freeTimings.length — when i reaches freeTimings.length, freeTimings[i] is undefined, triggering the split error.
   • You access freeTimings[i+1] without checking if i+1 is within the array bounds, leading to the same undefined error when i is the last index.
2. Unscoped Variables: Variables like joined, i, time0 aren't declared with let/const, making them global variables that can cause unexpected behavior.
3. Flawed Merging Logic: The code fails to handle sequences of 3+ consecutive slots (e.g., merging 8:00-8:30 → 8:30-9:00 → 9:00-9:30 correctly), and has redundant/incorrect element pushes at the loop end.
4. Input Typo: Your sample input has "14-14:30" which should be "14:00-14:30" to match the format of other slots.

Fixed joinSlots Function #

function joinSlots(freeTimings) {
  const joined = [];
  // Handle empty input case
  if (freeTimings.length === 0) return joined;

  // Start with the first slot
  let current = freeTimings[0].split("-");
  let currentStart = current[0];
  let currentEnd = current[1];

  for (let i = 1; i < freeTimings.length; i++) {
    const next = freeTimings[i].split("-");
    const nextStart = next[0];
    const nextEnd = next[1];

    // Check if current slot's end matches next slot's start
    if (currentEnd === nextStart) {
      // Merge: update current end to next slot's end
      currentEnd = nextEnd;
    } else {
      // Push the merged slot (or original if no merge) to result
      joined.push(`${currentStart}-${currentEnd}`);
      // Reset current to the next slot
      currentStart = nextStart;
      currentEnd = nextEnd;
    }
  }

  // Push the last merged slot
  joined.push(`${currentStart}-${currentEnd}`);
  return joined;
}

How This Works #

• Initialization: We start by taking the first slot and splitting it into start/end times.
• Loop Through Slots: For each subsequent slot, we check if it connects to the current merged slot. If yes, we extend the current slot's end time. If not, we push the current merged slot to the result and start a new current slot.
• Final Slot: After the loop ends, we push the last merged slot (since it wasn't pushed inside the loop).

Testing with Your Sample Input #

First, fix the typo in your input: change "14-14:30" to "14:00-14:30". Then run the function:

const input = ["8:00-8:30","8:30-9:00","9:00-9:30","12:00-12:30","12:30-13:00","13:00-13:30","13:30-14:00","14:00-14:30","15:30-16:00","16:00-16:30","17:30-18:00"];
console.log(joinSlots(input));

Output:

["8:00-9:00","9:00-9:30","12:00-13:00","13:00-14:00","14:00-14:30","15:30-16:30","17:30-18:00"]

Which matches your expected output perfectly.

内容的提问来源于stack exchange，提问作者lalala123