# Palindrome Partitioning Problem

## Description

LeetCode Problem 131.

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:

``````1
2
Input: s = "aab"
Output: [["a","a","b"],["aa","b"]]
``````

Example 2:

``````1
2
Input: s = "a"
Output: [["a"]]
``````

Constraints:

• 1 <= s.length <= 16
• s contains only lowercase English letters.

## Sample C++ Code

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class Solution {
public:
void dfs(vector<vector<int>>& dp, vector<vector<string>>& ans,
vector<string>& line, int idx, string& s) {
if (idx >= s.size()) {
ans.push_back(line);
return;
}
for (int i = idx; i < s.size(); i ++) {
if (dp[idx][i]) {
string t = s.substr(idx, i - idx + 1);
line.push_back(t);
dfs(dp, ans, line, i+1, s);
line.pop_back();
}
}
return;
}
vector<vector<string>> partition(string s) {
int len = s.size();
vector<vector<int>> dp(len, vector<int>(len, 1));

for (int i = 0; i < len; i ++) {
for (int j = i-1; j >= 0; j --) {
if (s[j] != s[i])
dp[j][i] = 0;
if (!dp[j+1][i-1])
dp[j][i] = 0;
}
}

vector<vector<string>> ans;
vector<string> line;
dfs(dp, ans, line, 0, s);
return ans;
}
};
``````