Overflow in intermediate arithmetic
Wrong move: Temporary multiplications exceed integer bounds.
Usually fails on: Large inputs wrap around unexpectedly.
Fix: Use wider types, modular arithmetic, or rearranged operations.
Build confidence with an intuition-first walkthrough focused on math fundamentals.
You are given a string date representing a Gregorian calendar date in the yyyy-mm-dd format.
date can be written in its binary representation obtained by converting year, month, and day to their binary representations without any leading zeroes and writing them down in year-month-day format.
Return the binary representation of date.
Example 1:
Input: date = "2080-02-29"
Output: "100000100000-10-11101"
Explanation:
100000100000, 10, and 11101 are the binary representations of 2080, 02, and 29 respectively.
Example 2:
Input: date = "1900-01-01"
Output: "11101101100-1-1"
Explanation:
11101101100, 1, and 1 are the binary representations of 1900, 1, and 1 respectively.
Constraints:
date.length == 10date[4] == date[7] == '-', and all other date[i]'s are digits.date represents a valid Gregorian calendar date between Jan 1st, 1900 and Dec 31st, 2100 (both inclusive).Problem summary: You are given a string date representing a Gregorian calendar date in the yyyy-mm-dd format. date can be written in its binary representation obtained by converting year, month, and day to their binary representations without any leading zeroes and writing them down in year-month-day format. Return the binary representation of date.
Start with the most direct exhaustive search. That gives a correctness anchor before optimizing.
Pattern signal: Math
"2080-02-29"
"1900-01-01"
number-of-1-bits)convert-to-base-2)Source-backed implementations are provided below for direct study and interview prep.
// Accepted solution for LeetCode #3280: Convert Date to Binary
class Solution {
public String convertDateToBinary(String date) {
List<String> ans = new ArrayList<>();
for (var s : date.split("-")) {
int x = Integer.parseInt(s);
ans.add(Integer.toBinaryString(x));
}
return String.join("-", ans);
}
}
// Accepted solution for LeetCode #3280: Convert Date to Binary
func convertDateToBinary(date string) string {
ans := []string{}
for _, s := range strings.Split(date, "-") {
x, _ := strconv.Atoi(s)
ans = append(ans, strconv.FormatUint(uint64(x), 2))
}
return strings.Join(ans, "-")
}
# Accepted solution for LeetCode #3280: Convert Date to Binary
class Solution:
def convertDateToBinary(self, date: str) -> str:
return "-".join(f"{int(s):b}" for s in date.split("-"))
// Accepted solution for LeetCode #3280: Convert Date to Binary
/**
* [3280] Convert Date to Binary
*/
pub struct Solution {}
// submission codes start here
use std::str::FromStr;
impl Solution {
pub fn convert_date_to_binary(date: String) -> String {
date.split('-')
.map(|x| u32::from_str(x).unwrap())
.map(|mut x| {
let mut result = vec![];
while x != 0 {
result.push(x % 2);
x = x / 2;
}
result
.iter()
.rev()
.map(|c| c.to_string())
.collect::<String>()
})
.reduce(|acc, e| acc + "-" + e.as_str())
.unwrap()
}
}
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_3280() {
assert_eq!(
"100000100000-10-11101".to_owned(),
Solution::convert_date_to_binary("2080-02-29".to_owned())
);
assert_eq!(
"11101101100-1-1".to_owned(),
Solution::convert_date_to_binary("1900-01-01".to_owned())
);
}
}
// Accepted solution for LeetCode #3280: Convert Date to Binary
function convertDateToBinary(date: string): string {
return date
.split('-')
.map(s => (+s).toString(2))
.join('-');
}
Use this to step through a reusable interview workflow for this problem.
Simulate the process step by step — multiply n times, check each number up to n, or iterate through all possibilities. Each step is O(1), but doing it n times gives O(n). No extra space needed since we just track running state.
Math problems often have a closed-form or O(log n) solution hidden behind an O(n) simulation. Modular arithmetic, fast exponentiation (repeated squaring), GCD (Euclidean algorithm), and number theory properties can dramatically reduce complexity.
Review these before coding to avoid predictable interview regressions.
Wrong move: Temporary multiplications exceed integer bounds.
Usually fails on: Large inputs wrap around unexpectedly.
Fix: Use wider types, modular arithmetic, or rearranged operations.