leetcode 291

 阻击回溯法。。。

#include <iostream>
#include<stdlib.h>
#include<string>
#include<vector>
#include<set>
#include<math.h>
#include<map>
#include<unordered_map>
#include<algorithm>
#include<functional>
#include<queue>
using namespace std;
map<char, string>mymap;//key为pattern中的字符串，value为该元素匹配的字符串
bool process(string pattern, string str) {
	if (pattern.empty())
		return str.empty();
	if (str.empty())
		return pattern.empty();
	//该字符尚未匹配
	if (mymap.find(pattern[0]) == mymap.end())
	{
		for (int i = 1; i < str.length(); i++) {
			mymap[pattern[0]] = str.substr(0, i);
			if (process(pattern.substr(1), str.substr(i)))
				return true;
		}
	}
	else {//当该字符已经匹配过了
		if (mymap[pattern[0]].length()>str.length())
			return false;
		if (mymap[pattern[0]] == str.substr(0, mymap[pattern[0]].length()))
			return process(pattern.substr(1), str.substr(mymap[pattern[0]].length()));
		else
			return false;
	}
	return false;
}


int main() {
	string pattern = "aaaa";
	string str = "asdasdasdasd";
	if (process(pattern,str)){
		for (int i = 0; i < pattern.length();i++) {
			cout << pattern[i] << ": " << mymap[pattern[i]]<<" "<<mymap[pattern[i]].length() << endl;
		}
	}
	system("pause");
	return 0;
}