Leetcode

Leetcode

一月 30, 2018

Record leetcode practices

Since My major is not computer science & softward engineering, I am not good at data structure and algorithm. In order to overcome it, I choose to do more relative practices in leetcode. Practice makes perfect.

I do practices by tags and from easy to difficult and I use javascript

Two sum

Description:

  • Given an array of integers, return indices of the two numbers such that they add up to a specific target.
  • You may assume that each input would have exactly one solution, and you may not use the same element twice.
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/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
  var result = [];
  nums.forEach(function(num, index) {
    if (index === nums.length - 1) {
      return;
    }
    var index2 = index + 1;
    for (var len = nums.length; index2 < len; index2++) {
      if (num + nums[index2] === target) {
        result = [index, index2];
        break;
      }
    }
  });
  return result;
};

Reverse Integer

Description:

  • Given a 32-bit signed integer, reverse digits of an integer.
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/**
 * @param {number} x
 * @return {number}
 */
var reverse = function(x) {
  var y = Math.abs(x) + "";
  y = y.split("").reverse();
  if (y[0] == 0) {
    y = y.slice(1);
  }
  if (+y.join("") > Math.pow(2, 31) - 1) {
    return 0;
  } else {
    if (x < 0) {
      y.unshift("-");
      y = y.join("");
    } else {
      y = y.join("");
    }
    return +y;
  }
};