Parity Game（并查集）

总时间限制: 10000ms
单个测试点时间限制: 1000ms
内存限制: 65536kB

描述
Now and then you play the following game with your friend. Your friend writes down a sequence consisting of zeroes and ones. You choose a continuous subsequence (for example the subsequence from the third to the fifth digit inclusively) and ask him, whether this subsequence contains even or odd number of ones. Your friend answers your question and you can ask him about another subsequence and so on. Your task is to guess the entire sequence of numbers. You suspect some of your friend’s answers may not be correct and you want to convict him of falsehood. Thus you have decided to write a program to help you in this matter. The program will receive a series of your questions together with the answers you have received from your friend. The aim of this program is to find the first answer which is provably wrong, i.e. that there exists a sequence satisfying answers to all the previous questions, but no such sequence satisfies this answer.

输入
The first line of input file PARITY.IN contains one number, which is the length of the sequence of zeroes and ones. This length is less or equal to 1000000000. In the second line, there is one positive integer which is the number of questions asked and answers to them. The number of questions and answers is less or equal to 5000. The remaining lines specify questions and answers. Each line contains one question and the answer to this question: two integers (the position of the first and
last digit in the chosen subsequence) and one word which is either even' orodd’ (the answer, i.e. the parity of the number of ones in the chosen subsequence, where even' means an even number of ones andodd’ means an odd number).

输出
There is only one line in output file PARITY.OUT containing one integer X. Number X says that there exists a sequence of zeroes and ones satisfying first X parity conditions, but there exists none satisfying X+1 conditions. If there exists a sequence of zeroes and ones satisfying all the given conditions, then number X should be the number of all the questions asked.

样例输入
10
5
1 2 even
3 4 odd
5 6 even
1 6 even
7 10 odd
样例输出
3

#include <iostream>
#include <cstring>
#include <algorithm>
#include <map>
#include <vector>
using namespace std;int parent[10005];
int rel[10005]; /* relation to the parent */
map<int, int> pos2idx;
vector<int> pos;
int length;
int N; /* number of answers */
int M; /* number of indexs */
int l[5005], r[5005];
bool v[5005];
char buf[5];int getroot(int cur)
{if (cur == parent[cur])return cur;int root = getroot(parent[cur]);rel[cur] = rel[parent[cur]] ^ rel[cur];parent[cur] = root;return root;
}/*** @return -1 if fail, 0 if normal*/
int merge(int i, int j, bool r_i_j)
{int root_i = getroot(i);int root_j = getroot(j);if (root_i == root_j) {/* check */if (r_i_j != (rel[i] ^ rel[j]))return -1;}else {/* merge */parent[root_i] = root_j; /* Attention: not parent[i] = j; !!! */rel[root_i] = rel[i] ^ rel[j] ^ r_i_j;}return 0;
}int main()
{cin >> length >> N;for (int i = 0; i < N; ++i) {scanf("%d %d %s", &l[i], &r[i], buf);++r[i];v[i] = buf[0] == 'o';pos.push_back(l[i]);pos.push_back(r[i]);}sort(pos.begin(), pos.end());auto it = unique(pos.begin(), pos.end());pos.erase(it, pos.end());M = pos.size();for (int i = 0; i < M; ++i) {pos2idx[pos[i]] = i;parent[i] = i;}int i;for (i = 0; i < N; ++i) {if (merge(pos2idx[l[i]], pos2idx[r[i]], v[i]) == -1)break;}printf("%d\n", i);system("pause");return 0;
}

Parity Game（并查集）相关推荐

P5937 [CEOI1999]Parity Game-扩展域并查集与离散化处理
题目链接[CEOI1999]Parity Game - 洛谷单调队列优化多重背包(全网最详细解析)_秦三马和他的CF生涯的博客-CSDN博客考察内容,扩展域并查集,本题中把奇偶性相同归为一个集合, ...
[POJ1733]Parity game（并查集 + 离散化）
传送门题意:有一个长度已知的01串,给出[l,r]这个区间中的1是奇数个还是偶数个,给出一系列语句问前几个是正确的思路:如果我们知道[1,2][3,4][5,6]区间的信息,我们可以求出[1,6] ...
Ural_1003 Parity(并查集)
/*发现并查集的应用太巧妙了...大体思路:从题中可以看出来如果(i, j)是even的话,sum(i-1) 和 sum(j)的奇偶性相同.(i, j)如果是odd的话则其奇偶行不同.定义奇偶性为朋友 ...
并查集——奇偶性（Parity）
题目描述 • 有一个 01 序列 , 长度 <=1000000000, 现在有 n 条信息 , 每条信息的形式是- a b even/odd .表示第 a 位到第 b 位元素之间的元素总和是 ...
Parity（带权值的并查集）
你的朋友写下一串包含1和0的串让你猜,你可以从中选择一个连续的子串(例如其中的第3到第5个数字)问他,该子串中包含了奇数个还是偶数个1,他会回答你的问题,然后你可以继续提问......你怀疑朋友的答案 ...
POJ 并查集题目汇总 ——czyuan原创（转）
继续数据结构的复习,本次的专题是:并查集. 并查集,顾名思义,干的就是"并"和"查"两件事.很多与集合相关的操作都可以用并查集高效的解决. 两个操作代码: ...
【无码专区9】序列统计（带权并查集 + 前缀和建边 + dp）
因为只有std,没有自我实现,所以是无码专区主要是为了训练思维能力 solution才是dls正解,但是因为只有潦草几句,所以大部分会有我自己基于正解上面的算法实现过程,可能选择的算法跟std中dl ...
【转】并查集MST题集
转自:http://blog.csdn.net/shahdza/article/details/7779230 [HDU] 1213 How Many Tables 基础并查集★ 1272 小希的迷宫 ...
[kuangbin带你飞]专题五并查集题解+总结
kuangbin带你飞:点击进入新世界总结: 本人算是初学者中的初学者,欢迎交流~ 并查集的接触过的不多,大概只有普通并查集,带权并查集,种族并查集,传说中的可持续化并查集只是听说过还没有接触,不过 ...
我知道并查集的可爱之处
请开始您的并查集之旅迈入门槛文字概念故事配图辅助理解浅尝辄止畅通工程程序自动分析 supermarket 慢慢深入银河英雄传说 parity game 1.带权并查集 2.扩展域并查集 ...

Parity Game（并查集）

Parity Game（并查集）相关推荐

最新文章

热门文章