如何在编码面试中口头解释你的 LeetCode 解法

Source: Dev.to

TL;DR

Why verbalize – 面试官评估的是 过程，而不仅仅是最终代码。沉默会让他们猜测你的能力；说出来则展示系统化思考。

What to say – 采用 UMPIRE 框架：Understand（理解），Match（匹配），Plan（计划），Implement（实现），Review（复盘），Evaluate（评估）。每个阶段都有具体的口头提示。

How to practice – 录下自己边说边解题的过程。刚开始会感觉别扭，但多练会变得自然。

When uncertain – 说 “我在思考 X” 或 “让我考虑两种方案” 而不是保持沉默。叙述你的推理，而不仅是你的动作。

Common mistake – 解释 你在写什么（“现在我在写一个循环”）而不是 为什么（“我需要循环来检查每个元素，因为……”）。

You’ll learn – 为每个面试阶段准备的结构化口头模板，如何自信地表达不确定性，以及能体现系统化思考的精准表达方式。

Why Silence Is Interpreted as Struggle

From the interviewer’s perspective

• 他们看不到你的思考过程。
• 沉默可能意味着：卡住了、困惑、在进展、或是放弃。
• 他们想帮助，但不知道你卡在哪儿。

From your perspective

• 你在深入思考。
• 你不想说错话。
• 你认为沉默 = 专注 = 高效。

The gap – 对你来说高效的状态，对他们来说却是令人担忧的信号。
The fix – 将内部独白外化。把面试官当作合作者，而不是评估者。

What “Thinking Out Loud” Actually Means

Not this (describing actions)

"I'm writing a for loop... now I'm declaring a variable... now I'm checking if..."

This (explaining reasoning)

// Example in JavaScript
// Explain why you choose each step
"I need to iterate through the array because I'm looking for pairs that meet a condition. 
I'm tracking seen values in a hash map so I can check if the complement exists in O(1) time. 
Let me code that up..."

The difference – 第二种展示了 为什么 这样做，证明你理解问题结构并做出了有意的选择。

This connects to broader interview communication strategies.

Step‑By‑Step Learning Guidance

Phase 1: Understand (Clarify the Problem)

What to say – 用自己的话复述问题并提出澄清性问题。

Template

"So if I understand correctly, we need to [restate problem].
The input is [describe input format and constraints].
The output should be [describe expected output].
Can I assume [clarifying question about edge cases or constraints]?"

Example

"So we're finding two numbers in the array that sum to the target value.
The input is an array of integers and a target number.
We should return the indices of those two numbers, not the values themselves.
Can I assume there's always exactly one solution, or should I handle the case where no solution exists?"

Why this works

• 展示你在考虑边界情况。
• 在编码前确认理解。
• 若有误解，可及时对话。

Phase 2: Match (Identify the Pattern)

What to say – 确认问题类型并说明选择的技术理由。

Template

"This looks like a [pattern/category] problem because [reasoning].
I'm thinking of using [data structure or algorithm] because [justification]."

Example

"This looks like a hash‑map problem because we need to find pairs that sum to a target, which means for each element we must quickly check if its complement exists. 
A hash map gives us O(1) lookup, which is better than the O(n²) brute‑force approach of checking every pair."

Why this works

• 展示模式识别能力。
• 表明你在考虑时间复杂度。
• 在编码前解释你的思路。

Phase 3: Plan (Outline Your Approach)

What to say – 在写代码前用高级语言描述算法。

Template

"Here's my approach:
1. [Step 1 in plain English]
2. [Step 2 in plain English]
3. [Step 3 in plain English]

The time complexity should be O([complexity]) because [reasoning].
Space complexity is O([complexity]) for [data structure]."

Example

"Here's my plan:
1. Create a hash map to store values we've seen and their indices.
2. Iterate through the array once.
3. For each element, calculate the complement (target minus current value).
4. Check if the complement exists in our map.
5. If yes, return those two indices; otherwise, add the current value to the map.

Time complexity is O(n) because we iterate once, and hash‑map operations are O(1).
Space complexity is O(n) in the worst case if we store every element."

Why this works

• 给面试官提供路线图。
• 让他们提前发现问题。
• 展示你对效率的考虑。

Phase 4: Implement (Code While Explaining)

What to say – 讲解关键决策和逻辑，而不是每一次敲键。

Template

"I'm [doing X] because [reason].
This handles [edge case or special condition].
Let me add [feature] to cover [scenario]."

Example (TypeScript/JavaScript)

// Explain while coding
"I'll initialize an empty hash map to track seen values..."
const seen = new Map();

"I now iterate through the array. For each element, I calculate the complement..."
for (let i = 0; i < nums.length; i++) {
  const complement = target - nums[i];

  "I check if the complement exists in the map. If it does, I've found my pair..."
  if (seen.has(complement)) {
    return [seen.get(complement)!, i];
  }

  "Otherwise, I store this value and move to the next element..."
  seen.set(nums[i], i);
}

What NOT to narrate

• 每个变量名的输入。
• 语法细节（“现在我在敲分号”）。
• 明显的操作（“按回车键”）。

What to narrate

• 为什么选择特定的数据结构。
• 如何处理边界情况。
• 关键的逻辑决策。