一、手写算法

https://leetcode-cn.com/problems/decode-string/

思路


  • 代码

    1. /**
    2. * @param {string} s
    3. * @return {string}
    4. */
    5. var decodeString = function(s) {
    6. let result = '',
    7.   numStack = [],
    8.   strStack = [],
    9.   num = 0;
    10. for (const char of s) {
    11.   if (!isNaN(char)) {
    12.     num = num * 10 + Number(char);
    13.   } else if (char === '[') {
    14.     strStack.push(result);
    15.     result = '';
    16.     numStack.push(num);
    17.     num = 0;
    18.   } else if (char === ']') {
    19.     let nu = numStack.pop();
    20.     result = strStack.pop() + result.repeat(nu);
    21.   } else {
    22.     result += char;
    23.   }
    24. }
    25. return result;
    26. };

    复杂度分析

  • 时间复杂度：O(n)

  • 空间复杂度：O(n)

二、编程题

  1. // 1.手写题：https://bigfrontend.dev/zh/problem/implement-Object.is
  1. function is(a,b) {
  2.    // SameValue algorithm
  3.     if (a === b) { // Steps 1-5, 7-10
  4.       // Steps 6.b-6.e: +0 != -0
  5.       return a !== 0 || 1 / a === 1 / b;
  6.     } else {
  7.       // Step 6.a: NaN == NaN
  8.       return a !== a && b !== b;
  9.     }
  10. }