Question

How to check whether each substring range (L to R) from an array of substring ranges is a palindrome in C++

Answer 1

#include <algorithm> // reverse
#include <iostream>
#include <string>

#define ROWS 3

bool isPalindrome(std::string str) {
    std::string rev = str;
    
    reverse(rev.begin(), rev.end());

    return str == rev;
}

void CheckRangesPalindrome(std::string str, int rows, int query[][2]) {
   for (int i = 0; i < rows; i++) {
        std::cout << str.substr(query[i][0], query[i][1] - query[i][0] + 1) << ": ";
        
        isPalindrome(str.substr(query[i][0], query[i][1] - query[i][0] + 1)) ? 
                std::cout << "Palindrome\n" : std::cout << "Not palindrome\n";
   }
}

int main() {
   std::string str = "abcddcbeebc"; 
   int ranges[ROWS][2] = {{2, 5}, {5, 10}, {3, 7}};
   
   CheckRangesPalindrome(str, ROWS, ranges);
}



/*
run:

cddc: Palindrome
cbeebc: Palindrome
ddcbe: Not palindrome

*/

 

70+ SQL courses for beginners and professionals

Answer 2

#include <iostream>
#include <string>

constexpr int ROWS = 3;

bool isPalindrome(const std::string& str, int left, int right) {
    while (left < right) {
        if (str[left++] != str[right--]) {
            return false;
        }
    }
    
    return true;
}

// Check and print whether substrings defined by ranges are palindromes
void checkRangesForPalindrome(const std::string& str, int rows, const int query[][2]) {
    for (int i = 0; i < rows; i++) {
        int start = query[i][0];
        int end = query[i][1];

        std::string substring = str.substr(start, end - start + 1);
        std::cout << substring << ": "
                  << (isPalindrome(str, start, end) ? "Palindrome" : "Not palindrome") << '\n';
    }
}

int main() {
    std::string str = "abcddcbeebc";
    
    const int ranges[ROWS][2] = {{2, 5}, {5, 10}, {3, 7}};

    checkRangesForPalindrome(str, ROWS, ranges);
}



/*
run:

cddc: Palindrome
cbeebc: Palindrome
ddcbe: Not palindrome

*/

 

70+ SQL courses for beginners and professionals