Add: Exercise 1679. Max Number of K-Sum Pairs

Author: BlackBeast593

1679-max-number-of-k-sum-pairs/README.md

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+# 1679. Max Number of K-Sum Pairs  
+Given an integer array `nums` and an integer `k`, the task is to find the maximum number of
+operations where each operation consists of removing a pair of numbers from the array that add up to
+`k`.  
+
+## Examples  
+
+### Example 1:  
+Input: `nums` = [1,2,3,4], `k` = 5
+
+Output: 2 
+
+Explanation:   
+- Remove numbers 1 and 4, making `nums` = [2,3].
+- Remove numbers 2 and 3.
+
+After this, there are no more pairs that sum up to 5, resulting in a total of 2 operations.  
+
+### Example 2:  
+Input: `nums` = [3,1,3,4,3], `k` = 6
+
+Output: 1
+
+Explanation:  
+- Remove the first two 3's, making `nums` = [1,4,3].
+
+There are no more pairs that sum up to 6, hence a total of 1 operation.
+
+## Constraints  
+- 1 <= `nums.length` <= 10^5  
+- 1 <= `nums[i]` <= 10^9  
+- 1 <= `k` <= 10^9  

1679-max-number-of-k-sum-pairs/index.js

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+/**
+ * Finds the maximum number of k-sum pairs in the array.
+ * @param {number[]} nums - The array of numbers.
+ * @param {number} k - The target sum for the pairs.
+ * @return {number} - The maximum number of k-sum pairs.
+ */
+var maxOperations = function(nums, k) {
+    const req = {}; // Object to store the required numbers to form a pair with each element.
+    let maxCount = 0; // Counter for the maximum number of k-sum pairs.
+    
+    for (const n of nums) {
+        const complement = k - n; // Calculate the complement number needed to reach k.
+
+        // If the complement exists in req, a pair is formed.
+        if (req[complement] >= 1) {
+            req[complement]--; // Decrement the count of the complement as it's now used.
+            maxCount++; // Increment the count of pairs.
+        } else {
+            // If the complement is not found, record the current number.
+            req[n] = (req[n] || 0) + 1;
+        }
+    }
+
+    return maxCount; // Return the total number of pairs formed.
+};
+
+// Example usage
+// var m = maxOperations([3,1,3,4,3], 6);
+
+module.exports = maxOperations

1679-max-number-of-k-sum-pairs/package.json

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+{
+  "name": "1679-max-number-of-k-sum-pairs",
+  "version": "1.0.0",
+  "description": "Given an integer array `nums` and an integer `k`, the task is to find the maximum number of operations where each operation consists of removing a pair of numbers from the array that add up to `k`.",
+  "main": "index.js",
+  "scripts": {
+    "start": "node index.js",
+    "debug": "node --inspect-brk index.js",
+    "test": "node test.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}

1679-max-number-of-k-sum-pairs/test.js

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+const assert = require('assert')
+const maxOperations = require('./index')
+
+const tests = [
+    {
+        nums: [1,2,3,4],
+        k: 5,
+        expected: 2,
+    },
+    {
+        nums: [3,1,3,4,3],
+        k: 6,
+        expected: 1,
+    },
+]
+
+for (const t of tests) {
+    assert.strict.deepEqual(maxOperations(t.nums, t.k), t.expected)
+}

README.md

@@ -17,11 +17,16 @@ You can use the following scripts on each exercise:
 {
   // ...
   "scripts": {
-    "start": "node index.js",               // Starts the program
-    "debug": "node --inspect-brk index.js", // Starts the program in debug mode
-    "test": "node test.js"                  // Run the test suite for this exercise
+    "start": "node index.js",
+    "debug": "node --inspect-brk index.js",
+    "test": "node test.js"
   },
   // ...
 }
 
 ```
+
+Where:
+- `start`: Starts the program
+- `debug`: Starts the program in debug mode
+- `test`: Run the test suite for this exercise