两数之和 #

给定一个整数数组 nums  和一个目标值 target，请你在该数组中找出和为目标值的那**两个**整数，并返回他们的数组下标。 你可以假设每种输入只会对应一个答案。但是，你不能重复利用这个数组中同样的元素。 示例: ``` 给定 nums = [2, 7, 11, 15], target = 9 因为 nums[0] + nums[1] = 2 + 7 = 9 所以返回 [0, 1] ```

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. Example: ``` Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1]. ```

使用 hash 表，记录过程数据，空间换时间

```c ```

```c++ ```

```c# ```

```go func twoSum(nums []int, target int) []int { tmp := make(map[int]int) for k, v := range(nums) { first, ok := tmp[v] if ok { return []int{first, k} } tmp[target - v] = k } return []int{} } ```

```java class Solution { public int[] twoSum(int[] nums, int target) { HashMap tmp = new HashMap(); for(int i = 0; i < nums.length; i++) { if (tmp.get(nums[i]) != null) { return new int[] {tmp.get(nums[i]), i}; } else { tmp.put(target - nums[i], i); } } return new int[] {}; } } ```

```javascript ```

```kotlin ```

```php ```

```python class Solution(object): def twoSum(self, nums, target): """ :type nums: List[int] :type target: int :rtype: List[int] """ r = {} for i in range(len(nums)): if nums[i] in r: return i, r[nums[i]] else: r[target - nums[i]] = i ```

```python class Solution: def twoSum(self, nums: List[int], target: int) -> List[int]: ```

```ruby ```

```rust ```

```scala ```

```swift ```

```typescript ```