1775. Equal Sum Arrays With Minimum Number of Operations: AC

Author: tan-wei

src/solution/mod.rs

@@ -1338,3 +1338,4 @@ mod s1770_maximum_score_from_performing_multiplication_operations;
 mod s1771_maximize_palindrome_length_from_subsequences;
 mod s1773_count_items_matching_a_rule;
 mod s1774_closest_dessert_cost;
+mod s1775_equal_sum_arrays_with_minimum_number_of_operations;

src/solution/s1775_equal_sum_arrays_with_minimum_number_of_operations.rs

@@ -0,0 +1,120 @@
+/**
+ * [1775] Equal Sum Arrays With Minimum Number of Operations
+ *
+ * You are given two arrays of integers nums1 and <font face="monospace">nums2</font>, possibly of different lengths. The values in the arrays are between 1 and 6, inclusive.
+ * In one operation, you can change any integer's value in any of the arrays to any value between 1 and 6, inclusive.
+ * Return the minimum number of operations required to make the sum of values in nums1 equal to the sum of values in nums2. Return -1​​​​​ if it is not possible to make the sum of the two arrays equal.
+ *  
+ * Example 1:
+ *
+ * Input: nums1 = [1,2,3,4,5,6], nums2 = [1,1,2,2,2,2]
+ * Output: 3
+ * Explanation: You can make the sums of nums1 and nums2 equal with 3 operations. All indices are 0-indexed.
+ * - Change nums2[0] to 6. nums1 = [1,2,3,4,5,6], nums2 = [<u>6</u>,1,2,2,2,2].
+ * - Change nums1[5] to 1. nums1 = [1,2,3,4,5,<u>1</u>], nums2 = [6,1,2,2,2,2].
+ * - Change nums1[2] to 2. nums1 = [1,2,<u>2</u>,4,5,1], nums2 = [6,1,2,2,2,2].
+ *
+ * Example 2:
+ *
+ * Input: nums1 = [1,1,1,1,1,1,1], nums2 = [6]
+ * Output: -1
+ * Explanation: There is no way to decrease the sum of nums1 or to increase the sum of nums2 to make them equal.
+ *
+ * Example 3:
+ *
+ * Input: nums1 = [6,6], nums2 = [1]
+ * Output: 3
+ * Explanation: You can make the sums of nums1 and nums2 equal with 3 operations. All indices are 0-indexed.
+ * - Change nums1[0] to 2. nums1 = [<u>2</u>,6], nums2 = [1].
+ * - Change nums1[1] to 2. nums1 = [2,<u>2</u>], nums2 = [1].
+ * - Change nums2[0] to 4. nums1 = [2,2], nums2 = [<u>4</u>].
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= nums1.length, nums2.length <= 10^5
+ * 	1 <= nums1[i], nums2[i] <= 6
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/equal-sum-arrays-with-minimum-number-of-operations/
+// discuss: https://leetcode.com/problems/equal-sum-arrays-with-minimum-number-of-operations/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn min_operations(nums1: Vec<i32>, nums2: Vec<i32>) -> i32 {
+        let a: i32 = nums1.iter().map(|&x| x as i32).sum();
+        let b = nums2.iter().map(|&x| x as i32).sum();
+
+        if (a < b) {
+            return Self::min_operations(nums2, nums1);
+        }
+
+        let mut pq = std::collections::BinaryHeap::new();
+        let mut amount = a - b;
+
+        for n in nums1 {
+            if n > 1 {
+                pq.push(n - 1);
+            }
+        }
+
+        for n in nums2 {
+            if n < 6 {
+                pq.push(6 - n);
+            }
+        }
+
+        let mut result = 0;
+
+        while amount > 0 && pq.is_empty() == false {
+            amount -= pq.pop().unwrap();
+            result += 1;
+        }
+
+        if amount > 0 {
+            return -1;
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1775_example_1() {
+        let nums1 = vec![1, 2, 3, 4, 5, 6];
+        let nums2 = vec![1, 1, 2, 2, 2, 2];
+
+        let result = 3;
+
+        assert_eq!(Solution::min_operations(nums1, nums2), result);
+    }
+
+    #[test]
+    fn test_1775_example_2() {
+        let nums1 = vec![1, 1, 1, 1, 1, 1, 1];
+        let nums2 = vec![6];
+
+        let result = -1;
+
+        assert_eq!(Solution::min_operations(nums1, nums2), result);
+    }
+
+    #[test]
+    fn test_1775_example_3() {
+        let nums1 = vec![6, 6];
+        let nums2 = vec![1];
+
+        let result = 3;
+
+        assert_eq!(Solution::min_operations(nums1, nums2), result);
+    }
+}