Palindrome Partitioning Given a string s
, partition s
such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s
.
A palindrome string is a string that reads the same backward as forward.
Example 1:
Input: s = "aab" Output: [["a","a","b"],["aa","b"]]
Example 2:
Input: s = "a" Output: [["a"]]
Constraints:
1 <= s.length <= 16
s
contains only lowercase English letters.
Palindrome Partitioning Solutions
✅Time: O(n)
✅Space: O(n)
C++
class Solution {
public:
vector<vector<string>> partition(string s) {
vector<vector<string>> ans;
dfs(s, 0, {}, ans);
return ans;
}
private:
void dfs(const string& s, int start, vector<string>&& path,
vector<vector<string>>& ans) {
if (start == s.length()) {
ans.push_back(path);
return;
}
for (int i = start; i < s.length(); ++i)
if (isPalindrome(s, start, i)) {
path.push_back(s.substr(start, i - start + 1));
dfs(s, i + 1, move(path), ans);
path.pop_back();
}
}
bool isPalindrome(const string& s, int l, int r) {
while (l < r)
if (s[l++] != s[r--])
return false;
return true;
}
};
Java
class Solution {
public List<List<String>> partition(String s) {
List<List<String>> ans = new ArrayList<>();
dfs(s, 0, new ArrayList<>(), ans);
return ans;
}
private void dfs(final String s, int start, List<String> path, List<List<String>> ans) {
if (start == s.length()) {
ans.add(new ArrayList<>(path));
return;
}
for (int i = start; i < s.length(); ++i)
if (isPalindrome(s, start, i)) {
path.add(s.substring(start, i + 1));
dfs(s, i + 1, path, ans);
path.remove(path.size() - 1);
}
}
private boolean isPalindrome(final String s, int l, int r) {
while (l < r)
if (s.charAt(l++) != s.charAt(r--))
return false;
return true;
}
}
Python
class Solution:
def partition(self, s: str) -> List[List[str]]:
ans = []
def isPalindrome(s: str) -> bool:
return s == s[::-1]
def dfs(s: str, j: int, path: List[str], ans: List[List[str]]) -> None:
if j == len(s):
ans.append(path)
return
for i in range(j, len(s)):
if isPalindrome(s[j: i + 1]):
dfs(s, i + 1, path + [s[j: i + 1]], ans)
dfs(s, 0, [], ans)
return ans
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