✨ [1512] Number of Good Pairs

Author: enkr1

1512/my_solution.js

@@ -0,0 +1,37 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+const numIdenticalPairs = (nums) => { // from chat gpt
+  let freq = {};
+  let count = 0;
+
+  // Count the frequency of each number
+  for (let num of nums) {
+    freq[num] = (freq[num] || 0) + 1;
+  }
+
+  console.log(freq)
+  // Calculate the number of good pairs for each number
+  for (let key in freq) {
+    let frequency = freq[key];
+    console.log(`${key} -> ${(frequency - 1) * frequency / 2}`)
+    count += ((frequency - 1) * frequency) / 2;
+  }
+
+  return count;
+}
+
+numIdenticalPairs([1, 2, 3, 1, 1, 3])
+
+// const numIdenticalPairs = (nums) => {
+//   let count = 0;
+//
+//   for (let i = 0; i < nums.length; i++) {
+//     for (let j = 0; j < nums.length; j++) {
+//       if (i < j && nums[i] === nums[j]) count++;
+//     }
+//   }
+//
+//   return count;
+// }

1512/solution.js

@@ -0,0 +1,23 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+const numIdenticalPairs = (nums) => { // from chat gpt
+  let freq = {};
+  let count = 0;
+
+  // Count the frequency of each number
+  for (let num of nums) {
+    freq[num] = (freq[num] || 0) + 1;
+  }
+
+  // Calculate the number of good pairs for each number
+  for (let key in freq) {
+    let frequency = freq[key];
+    count += (frequency - 1) * frequency / 2;
+  }
+
+  return count;
+}
+
+numIdenticalPairs([1, 2, 3, 1, 1, 3])

README.md

@@ -58,6 +58,7 @@
 - [647. Palindromic Substrings](./647/)
 - [771. Jewels and Stones](./771/)
 - [997. Find the Town Judge](./997/)
+- [1512. Number of Good Pairs](./1512/)
 - [1791. Find Center of Star Graph](./1791/)
 - [1971. Find if Path Exists in Graph](./1971/)
 
@@ -98,8 +99,8 @@ Batch create:
 <!--
 NOTE: JS IS HERE
 -->
-```**ssh**
-chapter=56 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
+```ssh
+chapter=1512 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
 ```
 > then you can use `x` for quick debug.