Improved task 1679.

Author: javadev

src/main/java/g1601_1700/s1679_max_number_of_k_sum_pairs/Solution.java

@@ -1,25 +1,28 @@
 package g1601_1700.s1679_max_number_of_k_sum_pairs;
 
 // #Medium #Array #Hash_Table #Sorting #Two_Pointers
+// #2022_04_21_Time_22_ms_(85.31%)_Space_67.1_MB_(70.80%)
 
-import java.util.HashMap;
-import java.util.Map;
+import java.util.Arrays;
 
 public class Solution {
  public int maxOperations(int[] nums, int k) {
- Map<Integer, Integer> map = new HashMap<>();
- int ops = 0;
- for (int num : nums) {
- if (map.containsKey(k - num)) {
- map.put(k - num, map.get(k - num) - 1);
- ops++;
- if (map.get(k - num) == 0) {
- map.remove(k - num);
- }
+ Arrays.sort(nums);
+ int i = 0;
+ int c = 0;
+ int j = nums.length - 1;
+ while (i < j) {
+ int sum = nums[i] + nums[j];
+ if (sum == k) {
+ c++;
+ i++;
+ j--;
+ } else if (sum > k) {
+ j--;
  } else {
- map.put(num, map.getOrDefault(num, 0) + 1);
+ i++;
  }
  }
- return ops;
+ return c;
  }
 }