Dsa Bit Count Bits

In this tutorial, you'll learn about How to Fix Counting Bits Errors. We cover key concepts, practical examples, and best practices.

Fix counting bits errors when DP uses array of size n+1 but recurrence off by one.

Quick Fix

Wrong

def count_bits(n):
    dp=[0]*(n+1)
    for i in range(1,n+1):
        if i%2==0: dp[i]=dp[i//2]
        else: dp[i]=dp[i-1]+1

Even: same count as i//2 (right shift). Odd: count of i-1 + 1. Works but can be simpler.

Right

def count_bits(n):
    dp=[0]*(n+1)
    for i in range(1,n+1):
        dp[i]=dp[i>>1]+(i&1)
    return dp

count_bits(5) = [0,1,1,2,1,2]. O(n).

Prevention

For even: right shift gives same count. For odd: right shift count + 1. Combine: dp[i] = dp[i>>1] + (i&1).

DodaTech Tools

Doda Browser's algorithm visualizer steps through DSA operations line by line. DodaZIP archives implementation patterns for team sharing. Durga Antivirus Pro detects memory corruption patterns in algorithm implementations.

FAQ