Leetcode 2311 Longest Binary Subsequence Less Than or Equal to K Solution in c++ | Hindi Coding Community

 

You are given a binary string s and a positive integer k.

Return the length of the longest subsequence of s that makes up a binary number less than or equal to k.

Note:

• The subsequence can contain leading zeroes.
• The empty string is considered to be equal to 0.
• A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.

 

Example 1:

Input: s = "1001010", k = 5
Output: 5
Explanation: The longest subsequence of s that makes up a binary number less than or equal to 5 is "00010", as this number is equal to 2 in decimal.
Note that "00100" and "00101" are also possible, which are equal to 4 and 5 in decimal, respectively.
The length of this subsequence is 5, so 5 is returned.

Example 2:

Input: s = "00101001", k = 1
Output: 6
Explanation: "000001" is the longest subsequence of s that makes up a binary number less than or equal to 1, as this number is equal to 1 in decimal.
The length of this subsequence is 6, so 6 is returned.

 

Constraints:

• 1 <= s.length <= 1000
• s[i] is either '0' or '1'.
• 1 <= k <= 109

C++ Code :

int longestSubsequence(string s, int k) {

int dp[1010] = {}, j = 0;

for (char& v : s) {

if (dp[j] * 2 + v - '0' <= k)

dp[++j] = dp[j] * 2 + v - '0';

for (int i = j; i > 0; --i)

dp[i] = min(dp[i], dp[i - 1] * 2 + v - '0');

}

return j;

}