3270. Find the Key of the Numbers
Description
You are given three positive integers num1
, num2
, and num3
.
The key
of num1
, num2
, and num3
is defined as a four-digit number such that:
- Initially, if any number has less than four digits, it is padded with leading zeros.
- The
ith
digit (1 <= i <= 4
) of thekey
is generated by taking the smallest digit among theith
digits ofnum1
,num2
, andnum3
.
Return the key
of the three numbers without leading zeros (if any).
Example 1:
Input: num1 = 1, num2 = 10, num3 = 1000
Output: 0
Explanation:
On padding, num1
becomes "0001"
, num2
becomes "0010"
, and num3
remains "1000"
.
- The
1st
digit of thekey
ismin(0, 0, 1)
. - The
2nd
digit of thekey
ismin(0, 0, 0)
. - The
3rd
digit of thekey
ismin(0, 1, 0)
. - The
4th
digit of thekey
ismin(1, 0, 0)
.
Hence, the key
is "0000"
, i.e. 0.
Example 2:
Input: num1 = 987, num2 = 879, num3 = 798
Output: 777
Example 3:
Input: num1 = 1, num2 = 2, num3 = 3
Output: 1
Constraints:
1 <= num1, num2, num3 <= 9999
Solutions
Solution 1: Simulation
We can directly simulate this process by defining a variable $\textit{ans}$ to store the answer and a variable $\textit{k}$ to represent the current digit place, where $\textit{k} = 1$ represents the units place, $\textit{k} = 10$ represents the tens place, and so on.
Starting from the units place, for each digit place, we calculate the current digit of $\textit{num1}$, $\textit{num2}$, and $\textit{num3}$, take the minimum of the three, and then add this minimum value multiplied by $\textit{k}$ to the answer. Then, multiply $\textit{k}$ by 10 and continue to the next digit place.
Finally, return the answer.
The time complexity is $O(1)$, and the space complexity is $O(1)$.
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