力扣Hot题题解(python,scala,java,c++)

没想到刚工作没多久就遇到了互联网寒冬，公司有大裁员的征兆。又要开始刷题了。
Leetcode 1 两数之和
https://leetcode-cn.com/problems/two-sum/

# python 1
class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        dic = {}
        result = []
        for i in range(len(nums)):
            if nums[i] not in dic:
                dic[target-nums[i]] = i
            else:
                result.append(dic[nums[i]])
                result.append(i)
        return result

//scala ver.1.
import scala.collection.mutable
object Solution {
    def twoSum(nums: Array[Int], target: Int): Array[Int] = {
        val map = new mutable.linkedHashMap[Int, Int]
        for(i <- nums.indices){
            if(map.contains(nums(i))){
                return Array(map(nums(i)),i)
            }else{
                map.put(target-nums(i), i)
            }
        }
        Array(0,0)
  }
// scala ver.2.
object Solution {
    def twoSum(nums: Array[Int], target: Int): Array[Int] = {
        var map: Map[Int,Int] = Map()
        for(i <- nums.indices){
            if(map.contains(nums(i))){
                return Array(map(nums(i)),i)
            }else{
                map += (target-nums(i) -> i)
            }
        }
        return Array(0,0)
  }
}