Add counting-bits solution in TS

Author: Jeehay28

counting-bits/Jeehay28.ts

@@ -0,0 +1,17 @@
+// TC: O(n)
+// SC: O(n)
+function countBits(n: number): number[] {
+  const dp: number[] = [];
+  dp[0] = 0;
+
+  for (let i = 0; i <= n; i++) {
+    dp[i] = dp[i >> 1] + (i & 1);
+  }
+
+  // The number of 1s in the quotient (i >> 1) + number of 1s in the remainder (i & 1)
+  // dp[i >> 1]: number of 1's in Math.floor(i / 2)
+  // i & 1: 1 if i is odd, 0 if even
+
+  return dp;
+}
+