minimum characters to make string palindrome

To find the minimum number of characters needed to make a string palindrome in C++, you can use the following approach:

1. Initialize two pointers, start and end, pointing to the start and end of the string, respectively.
2. Check if the characters at the start and end pointers are equal. If they are, move the start pointer one step forward and the end pointer one step backward.
3. If the characters at the start and end pointers are not equal, you have two options: a. Skip the character at the start pointer and move it one step forward. b. Skip the character at the end pointer and move it one step backward. Choose the option that results in the smallest number of additional characters added to make the string palindrome.
4. Repeat steps 2 and 3 until the start pointer reaches or surpasses the end pointer.
5. The number of characters skipped during the process is the minimum number of characters needed to make the string palindrome.

Here's an example implementation in C++:

#include <iostream>
#include <string>

int minCharsToMakePalindrome(const std::string& str) {
    int start = 0;
    int end = str.length() - 1;
    int count = 0;

    while (start < end) {
        if (str[start] == str[end]) {
            start++;
            end--;
        } else {
            if (str[start + 1] == str[end]) {
                start++;
                count++;
            } else if (str[start] == str[end - 1]) {
                end--;
                count++;
            } else {
                start++;
                end--;
                count += 2;
            }
        }
    }

    return count;
}

int main() {
    std::string str = "abcde";
    int minChars = minCharsToMakePalindrome(str);
    std::cout << "Minimum characters needed: " << minChars << std::endl;
    return 0;
}

In this example, the minCharsToMakePalindrome function takes a string str as its parameter and returns the minimum number of characters needed to make the string palindrome. The main function demonstrates how to use this function with an example string "abcde". The output will be the minimum characters needed, which in this case is 4.