feat: add solutions to lc problem: No.1679 (doocs#725)

No.1679.Max Number of K-Sum Pairs

Author: hongyiheng

solution/1600-1699/1679.Max Number of K-Sum Pairs/README.md

@@ -54,15 +54,46 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def maxOperations(self, nums: List[int], k: int) -> int:
+        nums.sort()
+        ans, l, r = 0, 0, len(nums) - 1
+        while l < r:
+            if nums[l] + nums[r] > k:
+                r -= 1
+            elif nums[l] + nums[r] < k:
+                l += 1
+            else:
+                ans += 1
+                l += 1
+                r -= 1
+        return ans
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public int maxOperations(int[] nums, int k) {
+        Arrays.sort(nums);
+        int l = 0, r = nums.length - 1;
+        int ans = 0;
+        while (l < r) {
+            if (nums[l] + nums[r] > k) {
+                r--;
+            } else if (nums[l] + nums[r] < k) {
+                l++;
+            } else {
+                ans++;
+                l++;
+                r--;
+            }  
+        }
+        return ans;
+    }
+}
 ```
 
 ### **...**

solution/1600-1699/1679.Max Number of K-Sum Pairs/README_EN.md

@@ -46,13 +46,44 @@ There are no more pairs that sum up to 6, hence a total of 1 operation.</pre>
 ### **Python3**
 
 ```python
-
+class Solution:
+    def maxOperations(self, nums: List[int], k: int) -> int:
+        nums.sort()
+        ans, l, r = 0, 0, len(nums) - 1
+        while l < r:
+            if nums[l] + nums[r] > k:
+                r -= 1
+            elif nums[l] + nums[r] < k:
+                l += 1
+            else:
+                ans += 1
+                l += 1
+                r -= 1
+        return ans
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public int maxOperations(int[] nums, int k) {
+        Arrays.sort(nums);
+        int l = 0, r = nums.length - 1;
+        int ans = 0;
+        while (l < r) {
+            if (nums[l] + nums[r] > k) {
+                r--;
+            } else if (nums[l] + nums[r] < k) {
+                l++;
+            } else {
+                ans++;
+                l++;
+                r--;
+            }  
+        }
+        return ans;
+    }
+}
 ```
 
 ### **...**

solution/1600-1699/1679.Max Number of K-Sum Pairs/Solution.java

@@ -0,0 +1,19 @@
+class Solution {
+    public int maxOperations(int[] nums, int k) {
+        Arrays.sort(nums);
+        int l = 0, r = nums.length - 1;
+        int ans = 0;
+        while (l < r) {
+            if (nums[l] + nums[r] > k) {
+                r--;
+            } else if (nums[l] + nums[r] < k) {
+                l++;
+            } else {
+                ans++;
+                l++;
+                r--;
+            }
+        }
+        return ans;
+    }
+}

solution/1600-1699/1679.Max Number of K-Sum Pairs/Solution.py

@@ -0,0 +1,14 @@
+class Solution:
+    def maxOperations(self, nums: List[int], k: int) -> int:
+        nums.sort()
+        ans, l, r = 0, 0, len(nums) - 1
+        while l < r:
+            if nums[l] + nums[r] > k:
+                r -= 1
+            elif nums[l] + nums[r] < k:
+                l += 1
+            else:
+                ans += 1
+                l += 1
+                r -= 1
+        return ans