rearranging fruits

greedy_methods/rearranging_fruits.py

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+# it's a leetcode question no. 2561 where You have two fruit baskets containing n fruits each. You are given two 0-indexed integer arrays basket1 and basket2 representing the cost of fruit in each basket.
+# You want to make both baskets equal. To do so, you can use the following operation as many times as you want:
+
+# Chose two indices i and j, and swap the ith fruit of basket1 with the jth fruit of basket2.
+# The cost of the swap is min(basket1[i],basket2[j]).
+# Two baskets are considered equal if sorting them according to the fruit cost makes them exactly the same baskets.
+
+# Return the minimum cost to make both the baskets equal or -1 if impossible.
+
+from typing import List
+from collections import defaultdict
+
+def min_cost(basket1: List[int], basket2: List[int]) -> int:
+    n = len(basket1)
+    freq = defaultdict(int)
+    mn = float("inf")
+
+    for i in range(n):
+        freq[basket1[i]] += 1
+        freq[basket2[i]] -= 1
+        mn = min(mn, basket1[i], basket2[i])
+
+    to_swap = []
+    for j, k in freq.items():
+        if k % 2 != 0:
+            return -1
+        to_swap += [j] * (abs(k) // 2)
+
+    to_swap.sort()
+    res = 0
+    for i in range(len(to_swap) // 2):
+        res += min(to_swap[i], 2 * mn)
+
+    return res
+
+
+if __name__ == "__main__":
+    # ---- Test Cases ----
+    test_cases = [
+        ([4, 2, 2, 2], [1, 4, 1, 2]),     # Expected: 1
+        ([1, 2, 3, 4], [2, 3, 4, 1]),     # Expected: 0
+        ([1, 1, 1, 1], [1, 1, 1, 1]),     # Expected: 0
+        ([1, 2, 2], [2, 1, 1]),           # Expected: -1
+        ([5, 3, 3, 2], [2, 5, 5, 3])      # Expected: -1
+    ]
+
+    print("Running test cases...\n")
+    for b1, b2 in test_cases:
+        print(f"basket1 = {b1}, basket2 = {b2} → minCost = {min_cost(b1, b2)}")