1.Two Sum

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].

Submissions

• golang

func twoSum(nums []int, target int) []int {
    var save map[int]int
    save = make(map[int]int)
    var res []int
    for i,num := range nums{
        if _, ok := save[target-num]; ok{
            res = append(res,save[target-num],i)
            break
        }else{
            save[num] = i
        }
    }
    return res
}

• java

class Solution {
    public int[] twoSum(int[] nums, int target) {
    Map<Integer, Integer> map = new HashMap<>();
    for (int i = 0; i < nums.length; i++) {
        map.put(nums[i], i);
    }
    for (int i = 0; i < nums.length; i++) {
        int complement = target - nums[i];
        if (map.containsKey(complement) && map.get(complement) != i) {
            return new int[] { i, map.get(complement) };
        }
    }
    throw new IllegalArgumentException("No two sum solution");
}
}