JAVA

Running Sum of 1d Array Leetcode

class Solution {
    public int[] runningSum(int[] nums) {
    int[] ans = new int[nums.length];
    ans[0] = nums[0];
    for (int i = 1; i < nums.length; i++)
        ans[i] = ans[i-1] + nums[i];
    return ans;
    }
}

two sum O(n) leetcode

//O(n) hashmaps C++ Two Sum leetcode 
class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int,int> map;
        for(int i=0; i<=nums.size();i++){
            int compliment=target-nums[i];
            if(map.count(compliment)==1){
                return {map[compliment],i};
            }
            else{
                map[nums[i]]=i;
            }
            
     	}
        return {-1,-1};
        
    }
};

running sum of 1d array leetcode solution

public int[] RunningSum(int[] nums) 
{
	int sum = 0;
	int[] result= new int[nums.Length];
	for(int i = 0; i < nums.Length; i++)
	{
		sum += nums[i];
		result[i] = sum;
	}

	return result;
}