HDU
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The Tyrell corporation uses a state-of-the-art electronic document system that controls all aspects of document creation, viewing, editing, and distribution. Document security is handled via access control lists (ACLs). An ACL defines a set of entities that have access to the document, and for each entity defines the set of rights that it has. Entities are denoted by uppercase letters; an entity might be a single individual or an entire division. Rights are denoted by lowercase letters; examples of rights are a for append, d for delete, e for edit, and r for read.
The ACL for a document is stored along with that document, but there is also a separate ACL log stored on a separate log server. All documents start with an empty ACL, which grants no rights to anyone. Every time the ACL for a document is changed, a new entry is written to the log. An entry is of the form ExR, where E is a nonempty set of entities, R is a nonempty set of rights, and x is either "+", "–", or "=". Entry E+R says to grant all the rights in R to all the entities in E, entry E–R says to remove all the rights in R from all the entities in E, and entry E=R says that all the entities in E have exactly the rights in R and no others. An entry might be redundant in the sense that it grants an entity a right it already has and/or denies an entity a right that it doesn't have. A log is simply a list of entries separated by commas, ordered chronologically from oldest to most recent. Entries are cumulative, with newer entries taking precedence over older entries if there is a conflict.
Periodically the Tyrell corporation will run a security check by using the logs to compute the current ACL for each document and then comparing it with the ACL actually stored with the document. A mismatch indicates a security breach. Your job is to write a program that, given an ACL log, computes the current ACL.
The ACL for a document is stored along with that document, but there is also a separate ACL log stored on a separate log server. All documents start with an empty ACL, which grants no rights to anyone. Every time the ACL for a document is changed, a new entry is written to the log. An entry is of the form ExR, where E is a nonempty set of entities, R is a nonempty set of rights, and x is either "+", "–", or "=". Entry E+R says to grant all the rights in R to all the entities in E, entry E–R says to remove all the rights in R from all the entities in E, and entry E=R says that all the entities in E have exactly the rights in R and no others. An entry might be redundant in the sense that it grants an entity a right it already has and/or denies an entity a right that it doesn't have. A log is simply a list of entries separated by commas, ordered chronologically from oldest to most recent. Entries are cumulative, with newer entries taking precedence over older entries if there is a conflict.
Periodically the Tyrell corporation will run a security check by using the logs to compute the current ACL for each document and then comparing it with the ACL actually stored with the document. A mismatch indicates a security breach. Your job is to write a program that, given an ACL log, computes the current ACL.
MC-p,SC+cYB=rde,B-dq,AYM+eGQ+tju,GH-ju,AQ-z,Q=t,QG-tJBL=fwa,H+wf,LD-fz,BJ-a,P=aw#
1:CSc2:AeBerMeYder3:4:BHJfwLPaw
哇··· QAQ,写了两个小时的模拟,整个学校的智商都被我拉低了,一遇到模拟题就怂,没有任何算法可言,就是利用非常暴力的方法,真的是暴力暴力秒天秒地,最后一发过,估计是数据太水了吧。
题意如下:
额-_-,题意吧,就是ExR型的操作,E代表用户,R表示权限,x代表三种操作(即‘-’‘+’‘=’),- 表示将用户E的权限R去掉,+ 表示给用户E加上权限R,= 表示重新给用户E授权R(以前的权限清除),这里要记住每个逗号隔开是一组ExR型的输入,E和R输入都不唯一,有可能多个权限对多个用户操作,实践是检验真理的唯一标准,说那么多不如解释一下样例来的实际,就解释一下第四个样例吧:
样例四:JBL=fwa,H+wf,LD-fz,BJ-a,P=awJBL=fwa 表示将用户JBL的权限重置,然后把权限fwa授给JBL
H+wf 表示将用户H的权限再加上wf两种权限
LD-fz 表示取消用户L和D的fz两种权限
BJ-a 表示取消用户B和J的a权限
P=aw 表示将用户P的权限重置,然后把权限aw授给P
最后把拥有权限的用户按照字典序输出来,有一点,相邻的用户如果权限一样,那么将会写在一起,比如样例一:不是1:CcSc,而是1:CSc
思路嘛,就是模拟了,能看懂代码就看吧。。。
//HDU 2723#include <map>#include <set>#include <cmath>#include <queue>#include <string>#include <vector>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define inf 0x3f3f3f3f#define eps 1e-10#define maxn 100005#define zero(a) fabs(a)<eps#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define pb(a) push_back(a)#define mem(a,b) memset(a,b,sizeof(a))#define LL long long#define lson step<<1#define rson step<<1|1#define MOD 1000000009#define sqr(a) ((a)*(a))using namespace std;char s[1050];int a[28][28];int main() {int m;//长度 int count = 1;char E[105];//代表授给权限的人 E char R[105];//代表所授的权限R while(~scanf("%s",s) && s[0] != '#') {m = strlen(s);mem(a , 0);int i = 0;for(; i < m; i++) { //一个比较繁琐的循环 if(i == 0 || s[i] == ',') { //当i=0或者s[i]=','的时候开始一段新的ExR int j = i , e = 0 , r = 0;//e 是E[]的下标, r 是R[]的下标 if(s[i] == ',') j++; // 如果是逗号就开始新的授权,即j++ for(; j < m; j++) {if(s[j] >= 'A' && s[j] <= 'Z')E[e++] = s[j]; //把授给权限的人记录下来 else break;}int t = -1;if(s[j] == '-') t = 0; // 0:- 1:+ 2:=else if(s[j] == '+') t = 1; // 此处用于记录操作是增加还是减少或者重置权限; else t = 2;j++; //j++ 开始记录所授的权限 for(; j < m; j++) {if(s[j] >= 'a' && s[j] <= 'z') {R[r++] = s[j];}else break;}//以上把E存在了E[]里,把R存在了R[]里; if(t == 0) { //减少权限操作 for(int I = 0; I < r; I++) {for(int J = 0; J < e; J++) {a[R[I]-'a'+1][E[J]-'A'+1] = 0; //把拥有权限的用户以及权限存在二维数组里 }}}else if(t == 1) { //增加权限操作 for(int I = 0; I < r; I++) {for(int J = 0; J < e; J++) {a[R[I]-'a'+1][E[J]-'A'+1] = 1;}}}else if(t == 2){ //重置权限操作 for(int I = 0; I < 28; I++) {for(int J = 0; J < e; J++) {a[I][E[J]-'A'+1] = 0;}}for(int I = 0; I < r; I++) {for(int J = 0; J < e; J++) {a[R[I]-'a'+1][E[J]-'A'+1] = 1;}}}}}int t = 1;int AC[1005];for(int j = 0; j < 28; j++) {for(i = 0; i < 28; i++)if(a[i][j]) {AC[t++] = j; //将所有的用户给记录下来 }}printf("%d:",count++);t = unique(AC+1,AC+t)-AC;//用于把记录下来的用户去重 int temp; //标记 for(int j = 1; j < t; j++) {if(AC[j]) {printf("%c",AC[j]-1+'A');}for(int k = j+1; k < t; k++) {temp = 1;for(int l = 1; l < 27; l++) {if(a[l][AC[j]] != a[l][AC[k]]) { //进行匹配; temp = 0;break;}}if(temp == 1 && AC[k]) {printf("%c",AC[k]-1+'A');AC[k]=0;}else break;}for(int k = 0; k < 28; k++) {if(a[k][AC[j]]) {printf("%c",k-1+'a');}}}printf("\n");}return 0;}
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