leetcode 131 —— 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.

For example, given s = "aab",
Return

  [
    ["aa","b"],
    ["a","a","b"]
  ]

思路: DP+ 回溯

class Solution {
public:
	vector<vector<string>> res;
	int n;
	vector<vector<string>> partition(string s) {
		n = s.size();
		vector<vector<bool>> dp(n,vector<bool>(n,false));
		for (int i = 0; i < n; i++){
			for (int j = 0; j < n-i; j++){
				if (s[j+i] == s[j]){
					if (i <= 1)
						dp[j][j+i] = true;
					else
						dp[j][j+i] = dp[j + 1][j+i-1];
				}
			}
		}
		vector<string> path;
		dfs(0, path, s, dp);
		return res;
	}
	void dfs(int level, vector<string> &path, string &s, vector<vector<bool>> &dp){
		if (level == n){
			res.push_back(path);
			return;
		}
		for (int i = level; i < s.size(); i++){
			if (dp[level][i]){
				path.push_back(s.substr(level, i - level + 1));
				dfs(i + 1, path, s, dp);
				path.pop_back();
			}
		}
	}
};