Longest Binary Subsequence Less Than or Equal to K | Leetcode 2311

class Solution {
public:
    int longestSubsequence(string s, int k) {
        int n = s.size();
        //Step-1: Keep all set bits until value exceeds k
        long long val = 0;
        int i=0;
        while(i<min(n,32)){
            if(s[n-i-1]=='1'){
                long long power = pow(2,i);
                if(val + power > k)
                    break;
                val += power;
            }
            i++;
        }
        //Step-2: Count the removed bits
        int removed_count = 0;
        while(i<n){
            if(s[n-i-1]=='1')
                removed_count++;
            i++;
        }
        return n-removed_count;
    }
};
/*
//JAVA
class Solution {
    public int longestSubsequence(String s, int k) {
        int n = s.length();
        // Step-1: Keep all set bits until value exceeds k
        long val = 0;
        int i = 0;
        while (i < Math.min(n, 32)) {
            if (s.charAt(n - i - 1) == '1') {
                long power = (long) Math.pow(2, i);
                if (val + power > k) {
                    break;
                }
                val += power;
            }
            i++;
        }
        // Step-2: Count the removed bits
        int removed_count = 0;
        while (i < n) {
            if (s.charAt(n - i - 1) == '1') {
                removed_count++;
            }
            i++;
        }
        return n - removed_count;
    }
}

#Python
class Solution:
    def longestSubsequence(self, s: str, k: int) -> int:
        n = len(s)
        # Step-1: Keep all set bits until value exceeds k
        val = 0
        i = 0
        while i < min(n, 32):
            if s[n - i - 1] == '1':
                power = 2 ** i
                if val + power > k:
                    break
                val += power
            i += 1
        # Step-2: Count the removed bits
        removed_count = 0
        while i < n:
            if s[n - i - 1] == '1':
                removed_count += 1
            i += 1
        return n - removed_count
*/