programming-challenges Crypt Kicker (110204) 题解

我的解答,但是复杂度不是很满意,是一个指数级的复杂度.但是测试数据比较弱,还是ac了。在网上找了找，都是brute force的解法，不知道有没有更好的解法。

解答中犯了两个错误，第一个，map<int, vector<int>> 的定义不被接受。但是这肯定是一个合法的c++定义。第二个，忘了考虑映射字符间反向的约束。也就是"ab"可能会被翻译成"cc"，这是错误的。字符间从源到目标，从目标到源，都应该不存在一对多的映射。

#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <assert.h>
#include <algorithm>
#include <math.h>
#include <ctime>
#include <functional>
#include <string.h>
#include <stdio.h>
#include <numeric>
#include <float.h>

using namespace std;

vector<string> words;
vector<string> m_dic[81];
vector<int> finalMatchRelation; 

bool findMatchString(int index, vector<int> matchedCharacter, vector<int> getMatched) {
	if (index >= words.size()) {
		finalMatchRelation = matchedCharacter;
		return true;
	}

	vector<int> matchedCharacterBackup = matchedCharacter;
	vector<int> getMatchedBackup = getMatched; 

	int l = words[index].size();
	for (int i = 0; i < m_dic[l].size(); i++) {
		bool ok = true;
		for (int j = 0; j < words[index].size() && ok; j++) {
			int srcCharIndex = words[index][j] - 'a';
			int objCharIndex = m_dic[l][i][j] - 'a'; 

			if (matchedCharacter[srcCharIndex] == -1 && getMatched[objCharIndex] == -1) {
				matchedCharacter[srcCharIndex] = objCharIndex;
				getMatched[objCharIndex] = srcCharIndex;
			}
			else if (matchedCharacter[srcCharIndex] == (m_dic[l][i][j] - 'a')) {
				continue;
			}
			else {
				ok = false;
			}
		}

		if (ok) {
			bool goodResult = findMatchString(index + 1, matchedCharacter, getMatched);
			if (goodResult) {
				return true;
			}
		}

		matchedCharacter = matchedCharacterBackup;
		getMatched = getMatchedBackup;
	}
	return false;
}

int main() {
	string placeHolder;
	int n;
	cin >> n;
	getline(cin, placeHolder); 

	for (int i = 0; i < n; i++) {
		string ts;
		getline(cin, ts);
		m_dic[ts.size()].push_back(ts);
	}

	string s;
	while (getline(cin, s)) {
		vector<int> matchRelation(26, -1), getMatched(26, -1); 

		stringstream ss(s);
		string ts;
		words.clear();
		while (ss >> ts) {
			words.push_back(ts);
		}

		string result = "";
		if (findMatchString(0, matchRelation, getMatched)) {
			for (int i = 0; i < s.size(); i++) {
				if (s[i] == ' ')
					result.push_back(' ');
				else
					result.push_back('a' + finalMatchRelation[s[i] - 'a']);
			}
		}
		else {
			for (int i = 0; i < s.size(); i++) {
				if (s[i] == ' ')
					result.push_back(' ');
				else
					result.push_back('*');
			}
		}
		cout << result << endl;
	}

	return 0;
}