# 两数之和为k

java

```
```

python

```python
'''
找出数组中和为某个数的两个数的序号
思路：和为k等价与k-a=b，建立字典，遍历每个元素ai
如果k-ai不存在字典中就记下ai的位置i来，到下一个数如果k-aj=ai在字典中，那么结果就是(i,j)
'''


class Solution:
    def call(self, nums, target):
        hashset = {}
        for i, m in enumerate(nums):
            if target - m not in hashset:
                hashset[m] = i
            else:
                return (hashset[target - m] , i )


s = Solution()
print(s.call([2, 5, 7, 11, 15], 9))
```


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