Add number-of-1-bits solution in TypeScript

Author: Jeehay28

number-of-1-bits/Jeehay28.ts

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+// Approach 2
+// 🗓️ 2025-04-15
+// ⏳ Time Complexity: O(log n)
+// 💾 Space Complexity: O(1)
+
+function hammingWeight(n: number): number {
+  // n(이진수) & 1 -> 1: 이진수 n의 마지막 비트가 1인 경우에만 1 반환
+  // n(이진수) >> 1: 마지막 비트 제거
+  // 🔍 In binary numbers:
+  // Decimal: 11
+  // Binary:  1   0   1   1
+  //          ↑           ↑
+  //         MSB         LSB
+  //     (Most Sig.)   (Least Sig.)
+  // n & 1: only checks the least significant bit (LSB), if the LSB is 1, the result is 1.
+  // n >>= 1: Each bit is moved one place to the right.
+
+  let count = 0;
+
+  while (n) {
+    count += n & 1; // add 1 if the least significant bit of n is 1
+    n >>= 1; // The LSB is removed (dropped).
+  }
+
+  return count;
+}
+
+
+// Approach 1
+// 🗓️ 2025-04-15
+// ⏳ Time Complexity: O(log n)
+// 💾 Space Complexity: O(1)
+
+// function hammingWeight(n: number): number {
+//   // input: a positive number n
+//   // output: the number of set bits in binary representation
+//   // set bits: a bit in the binary representaton of a number that has a value of 1
+//   // 11 -> 1011 -> 3
+
+//   let cnt = 0;
+//   while (n > 0) {
+//     if (n % 2 === 1) {
+//       cnt += 1;
+//     }
+//     n = Math.floor(n / 2);
+//   }
+
+//   return cnt;
+// }
+