2570: Merge-Two-2D-Arrays-by-Summing-Values
Easy

table of contents

I start off with 2 pointers, i1 = 0 and i2 = 0, which are used to iterate through nums1 and nums2 respectively.

Creating ans as our resultant array, since both nums1 and nums2 are in ascending order, if:

We can repeat the conditional until we reach the end of nums1 or nums2 (or both).

Finally, to complete ans, we can just append all the remaining elements in either nums1 or nums2 before simply returning ans.

code

class Solution {
public:
    vector<vector<int>> mergeArrays(vector<vector<int>>& nums1, vector<vector<int>>& nums2) {
        int i1 = 0;
        int i2 = 0;

        vector<vector<int>> ans;
        while (i1 < nums1.size() && i2 < nums2.size()) {
            if (nums1[i1][0] == nums2[i2][0]) {
                ans.push_back({nums1[i1][0], nums1[i1][1] + nums2[i2][1]});
                ++i1;
                ++i2;
            } else if (nums1[i1][0] <= nums2[i2][0])  {
                ans.push_back({nums1[i1][0], nums1[i1][1]});
                ++i1;
            } else {
                ans.push_back({nums2[i2][0], nums2[i2][1]});
                ++i2;
            }
        }

        while (i1 < nums1.size()) {
            ans.push_back({nums1[i1][0], nums1[i1][1]});
            ++i1;
        }
        
        while (i2 < nums2.size()) {
            ans.push_back({nums2[i2][0], nums2[i2][1]});
            ++i2;
        }

        return ans;
    }
};

complexity