1480. Running Sum of 1d Array [Leetcode][C++]

class Solution { public: vector<int> runningSum(vector<int>& nums) { // Brute Force Solution Time O(N^2) & Auxiliary Space O(1) vector<int> result; int len=nums.size(),sum=0; for(int i=0;i<len;i++){ sum=0; for(int j=0;j<=i;j++){ sum+=nums[j]; } result.push_back(sum); } return result; } }; 

class Solution { public: vector<int> runningSum(vector<int>& nums) { // Optimal Solution Time O(N) & Auxiliary Space O(1) int len=nums.size(); for(int i=1;i<len;i++){ nums[i]+=nums[i-1]; } return nums; } };