LeetCode——Palindrome Partition

class Solution {
public:
	vector<string> vt;
	vector<vector<string> > ans;
	vector<vector<int> > dp;
	int len;
	bool dpjudge(string &s, int i, int j) {
		if (i > j) {
			return false;
		}
		if (dp[i][j] != -1) { //说明已经计算过
			return dp[i][j];
		}
		if (i == j) {
			return dp[i][j] = 1;
		}
		if (s[i] != s[j]) {
			return dp[i][j] = 0;
		} else {
			if (i + 1 == j) {
				return dp[i][j] = 1;
			} else {
				return dp[i][j] = dpjudge(s, i + 1, j - 1);
			}
		}
	}

	void dfs(string &s, int cnt) {
		if (cnt == len) {
			ans.push_back(vt);
			return;
		}
		for (int i = len - 1; i >= cnt; i--) {
			if (dpjudge(s, cnt, i)) {
				vt.push_back(s.substr(cnt, i - cnt + 1));
				dfs(s, i + 1);
				vt.pop_back();
			}
		}
	}
	vector<vector<string>> partition(string s) {
		vt.clear();
		ans.clear();
		dp.clear();
		len = s.length();
		vector<int> tmp;
		//初始化dp为-1
		for (int i = 0; i < len; i++) {
			tmp.push_back(-1);
		}
		for (int j = 0; j < len; j++) {
			dp.push_back(tmp);
		}
		dfs(s, 0);
		return ans;

	}
};