Added task 1674.

Author: javadev

src/main/java/g1601_1700/s1674_minimum_moves_to_make_array_complementary/Solution.java

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+package g1601_1700.s1674_minimum_moves_to_make_array_complementary;
+
+// #Medium #Array #Hash_Table #Prefix_Sum #2022_04_19_Time_29_ms_(22.22%)_Space_96.3_MB_(14.29%)
+
+public class Solution {
+ public int minMoves(int[] nums, int limit) {
+ int[] cnt = new int[limit * 2 + 1];
+ int[] min = new int[limit * 2 + 1];
+ int[] max = new int[limit * 2 + 2];
+ int n = nums.length;
+ int res = Integer.MAX_VALUE;
+ for (int i = 0; i < n / 2; i++) {
+ cnt[nums[i] + nums[n - i - 1]]++;
+ min[Math.min(nums[i], nums[n - i - 1])]++;
+ max[Math.max(nums[i], nums[n - i - 1]) + limit + 1]++;
+ }
+ for (int i = limit * 2 - 1; i >= 2; i--) {
+ min[i] += min[i + 1];
+ }
+ for (int i = 3; i < limit * 2 + 1; i++) {
+ max[i] += max[i - 1];
+ }
+ for (int i = 2; i < limit * 2 + 1; i++) {
+ res = Math.min(res, n / 2 - cnt[i] + min[i] + max[i]);
+ }
+ return res;
+ }
+}

src/main/java/g1601_1700/s1674_minimum_moves_to_make_array_complementary/readme.md

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+1674\. Minimum Moves to Make Array Complementary
+
+Medium
+
+You are given an integer array `nums` of **even** length `n` and an integer `limit`. In one move, you can replace any integer from `nums` with another integer between `1` and `limit`, inclusive.
+
+The array `nums` is **complementary** if for all indices `i` (**0-indexed**), `nums[i] + nums[n - 1 - i]` equals the same number. For example, the array `[1,2,3,4]` is complementary because for all indices `i`, `nums[i] + nums[n - 1 - i] = 5`.
+
+Return the _**minimum** number of moves required to make_ `nums` _**complementary**_.
+
+**Example 1:**
+
+**Input:** nums = [1,2,4,3], limit = 4
+
+**Output:** 1
+
+**Explanation:** In 1 move, you can change nums to [1,2,2,3] (underlined elements are changed).
+
+nums[0] + nums[3] = 1 + 3 = 4.
+
+nums[1] + nums[2] = 2 + 2 = 4.
+
+nums[2] + nums[1] = 2 + 2 = 4.
+
+nums[3] + nums[0] = 3 + 1 = 4.
+
+Therefore, nums[i] + nums[n-1-i] = 4 for every i, so nums is complementary.
+
+**Example 2:**
+
+**Input:** nums = [1,2,2,1], limit = 2
+
+**Output:** 2
+
+**Explanation:** In 2 moves, you can change nums to [2,2,2,2]. You cannot change any number to 3 since 3 > limit.
+
+**Example 3:**
+
+**Input:** nums = [1,2,1,2], limit = 2
+
+**Output:** 0
+
+**Explanation:** nums is already complementary.
+
+**Constraints:**
+
+* `n == nums.length`
+* <code>2 <= n <= 10<sup>5</sup></code>
+* <code>1 <= nums[i] <= limit <= 10<sup>5</sup></code>
+* `n` is even.

src/test/java/g1601_1700/s1674_minimum_moves_to_make_array_complementary/SolutionTest.java

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+package g1601_1700.s1674_minimum_moves_to_make_array_complementary;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class SolutionTest {
+ @Test
+ void minMoves() {
+ assertThat(new Solution().minMoves(new int[] {1, 2, 4, 3}, 4), equalTo(1));
+ }
+
+ @Test
+ void minMoves2() {
+ assertThat(new Solution().minMoves(new int[] {1, 2, 2, 1}, 2), equalTo(2));
+ }
+
+ @Test
+ void minMoves3() {
+ assertThat(new Solution().minMoves(new int[] {1, 2, 1, 2}, 2), equalTo(0));
+ }
+}