(C++ : Quize) Palindromic Substring

Posted by : C++ at Mar 31, 2021

Category : Cpp Quize

Q

문자열 가운데 대칭된 문자열을 찾아라, 없다면 none

Input: "hellosannasmith"
Output: sannas

Input: "abcdefgg"
Output: none

Write Code

Test Link

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

string PalindromicSubstring(string str) {
  // code
  return str;
}

int main(void) { 
   
  // keep this function call here
  cout << PalindromicSubstring("hellosannasmith");
  return 0;
}

A

for문을 두 개 돌리며 하나씩 비교해가는것이 핵심.

  for (int length = str.length(); length > 1 ; --length) {
    for (int i = 0; i < str.length()-length; ++i) {

A - Code

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

bool isPalindrome(std::string word) {
  std::string word2 = word;
  std::reverse(word2.begin(), word2.end());
  return word == word2;
}

string PalindromicSubstring(string str) {
  for (int length = str.length(); length > 1 ; --length) {
    for (int i = 0; i < str.length()-length; ++i) {
      std::string word = str.substr(i, length);
      if (isPalindrome(word)) {
        return word;
      }
    }
  }  
  return "none";

}

int main(void) { 
   
  // keep this function call here
  cout << PalindromicSubstring(coderbyteInternalStdinFunction(stdin));
  return 0;
}