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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-i-arrays-strings-hash-maps/lc-299-bulls-and-cows-implementation

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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-i-arrays-strings-hash-maps/lc-299-bulls-and-cows-implementation

Repovive

LeetCode 299 Bulls and Cows - Implementation - Coding Patterns I: Arrays, Strings & Hash Maps | Google Interview Prep | Repovive

Repovive.

Google Interview Prep6 sections · 128 units7h total

Open in Course

LeetCode 299 Bulls and Cows - Implementation

The code

Count bulls directly. Track digit frequencies in a single array to count cows in one pass.

function getHint(secret, guess):
    bulls = 0
    cows = 0
    counts = array of 10 zeros
    for i from 0 to len(secret) - 1:
        s = int(secret[i])
        g = int(guess[i])
        if s == g:
            bulls += 1
        else:
            if counts[s] < 0:
                cows += 1
            if counts[g] > 0:
                cows += 1
            counts[s] += 1
            counts[g] -= 1
    return str(bulls) + "A" + str(cows) + "B"

$O(n)$ time, $O(1)$ space.