merge-similar-items_2363.py

# You are given two 2D integer arrays, items1 and items2, representing two sets of items. Each array items has the following properties:

# items[i] = [valuei, weighti] where valuei represents the value and weighti represents the weight of the ith item.
# The value of each item in items is unique.
# Return a 2D integer array ret where ret[i] = [valuei, weighti], with weighti being the sum of weights of all items with value valuei.

# Note: ret should be returned in ascending order by value.
# Example 1:

# Input: items1 = [[1,1],[4,5],[3,8]], items2 = [[3,1],[1,5]]
# Output: [[1,6],[3,9],[4,5]]
# Explanation:
# The item with value = 1 occurs in items1 with weight = 1 and in items2 with weight = 5, total weight = 1 + 5 = 6.
# The item with value = 3 occurs in items1 with weight = 8 and in items2 with weight = 1, total weight = 8 + 1 = 9.
# The item with value = 4 occurs in items1 with weight = 5, total weight = 5.
# Therefore, we return [[1,6],[3,9],[4,5]].
# Example 2:

# Input: items1 = [[1,1],[3,2],[2,3]], items2 = [[2,1],[3,2],[1,3]]
# Output: [[1,4],[2,4],[3,4]]
# Explanation:
# The item with value = 1 occurs in items1 with weight = 1 and in items2 with weight = 3, total weight = 1 + 3 = 4.
# The item with value = 2 occurs in items1 with weight = 3 and in items2 with weight = 1, total weight = 3 + 1 = 4.
# The item with value = 3 occurs in items1 with weight = 2 and in items2 with weight = 2, total weight = 2 + 2 = 4.
# Therefore, we return [[1,4],[2,4],[3,4]].
# Example 3:

# Input: items1 = [[1,3],[2,2]], items2 = [[7,1],[2,2],[1,4]]
# Output: [[1,7],[2,4],[7,1]]
# Explanation:
# The item with value = 1 occurs in items1 with weight = 3 and in items2 with weight = 4, total weight = 3 + 4 = 7.
# The item with value = 2 occurs in items1 with weight = 2 and in items2 with weight = 2, total weight = 2 + 2 = 4.
# The item with value = 7 occurs in items2 with weight = 1, total weight = 1.
# Therefore, we return [[1,7],[2,4],[7,1]].

# ---------------------------------------Runtime 107 ms Beats 71.48% Memory 17.22 MB Beats 95.64%---------------------------------------

from typing import List


class Solution:
    def mergeSimilarItems(
        self, items1: List[List[int]], items2: List[List[int]]
    ) -> List[List[int]]:
        items_map = {}
        union = sorted((items1 + items2), key=lambda x: x[0])

        for key, value in union:
            items_map[key] = items_map.get(key, 0) + value

        return items_map.items()