Minimize the number of 0s that need to be removed to maximize the length of the longest consecutive 1 substring

In this article, we will delve into an interesting problem involving C string operations. The problem we are going to study today is how to "minimize the number of 0s that need to be deleted to maximize the length of the longest continuous substring of 1s." This problem is a great way to hone your skills in string manipulation and dynamic programming.

Problem Statement

Given a binary string, the task is to minimize the number of 0s that need to be removed in order to maximize the length of the longest 1 substring.

C Solution

In order to solve this problem, we can use the sliding window method. We will maintain two pointers, left pointer and right pointer. Initially, both pointers point to the first element. Then we'll keep moving the right pointer to the right. If a '0' is encountered, we increment a counter. If the counter becomes larger than the allowed number of zero removals, we move the left pointer right until we encounter a '0' and decrement the counter.

We will also maintain a variable maxLen to store the maximum length of the 1 substring we have seen so far.

Example

This is the C code that solves the problem -

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

int maxSubstring(string str, int k) {
   int zeroCount = 0;
   int left = 0;
   int maxLen = 0;
   
   for (int right = 0; right < str.size(); right++) {
      if (str[right] == '0') {
         zeroCount++;
      }
      while (zeroCount > k) {
         if (str[left] == '0') {
               zeroCount--;
         }
         left++;
      }
      maxLen = max(maxLen, right - left + 1);
   }
   return maxLen;
}

int main() {
   string str = "110100110";
   int k = 2; // number of zeros that can be removed
   int result = maxSubstring(str, k);
   cout << "The maximum length of the substring of 1s is: " << result << endl;
   return 0;
}

Output

The maximum length of the substring of 1s is: 5

Test case description

Let's take the binary string "110100110", we can remove 2 zeros.

When we pass this string and the value of k to the maxSubstring function, it starts scanning from the left. Whenever it encounters a '0', it increments zeroCount. When zeroCount exceeds k, it starts moving the left pointer to the right until it encounters a '0' and decrements zeroCount.

In this process, it continuously updates maxLen, which is the maximum substring length of 1s. For the given string, the maximum substring length of 1s without removing at most 2 zeros is 5, i.e. the substring "11111" after removing the second and third '0'.

Therefore, the function will return 5.

in conclusion

This question demonstrates how to effectively use sliding window techniques to solve complex string manipulation problems in C. This is an excellent question for understanding and practicing dynamic programming and string processing techniques. Keep practicing such questions to improve your C coding skills.

The above is the detailed content of Minimize the number of 0s that need to be removed to maximize the length of the longest consecutive 1 substring. For more information, please follow other related articles on the PHP Chinese website!