《算法竞赛入门经典2ndEdition 》例题5-5 集合栈计算机(The SetStack Computer, Uva12096)

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <vector>
#include <stack>
#include <map>
using namespace std;

typedef set<int> Set;
map<int, Set> ID;
stack<int> st;
int cnt;

int getID(Set);

int main()
{
freopen("New Text Document.txt","r",stdin);
freopen("Output.txt","w",stdout);
ios::sync_with_stdio(false);
int t, n;
string s;
cin>>t;
cin.get();
while(t--)
{
cnt = 0;
while(!st.empty()) st.pop();
//ID.clear();
cin>>n;
while(n--)
{
cin>>s;
//cout<<s<<endl;
if(s[0] == 'P') st.push(getID(Set()));
else if(s[0] == 'D') st.push(st.top());
else
{
Set s1 = ID[st.top()]; st.pop();
Set s2 = ID[st.top()]; st.pop();
Set s3;
s3.clear();
if(s[0] == 'U')
{
set_union(s1.begin(), s1.end(), s2.begin(), s2.end(), insert_iterator<Set>(s3, s3.begin()));
st.push(getID(s3));
}
if(s[0] == 'I')
{
set_intersection(s1.begin(), s1.end(), s2.begin(), s2.end(), insert_iterator<Set>(s3, s3.begin()));
st.push(getID(s3));
}
if(s[0] == 'A')
{
s2.insert(getID(s1));
st.push(getID(s2));
}
}
Set s = ID[st.top()];
cout<<s.size()<<endl;
}
//cout<<cnt;
//while(!st.empty())
//    {
//      cout<<ID[st.top()].size()<<endl;
//      st.pop();
//    }
//for(int i = 1; i <= cnt; i++)
//cout<<ID[i].size();
cout<<"***"<<endl;
}
return 0;
}

int getID(Set s)
{
for(int i = 1; i <= cnt; i++)
if(ID[i] == s) return i;
ID[++cnt] = s;//之前一直没写这个导致出错，没有将新集合加入到映射数组ID中
return cnt;
}

// UVa12096 The SetStack Computer
// Rujia Liu
#include<iostream>
#include<string>
#include<set>
#include<map>
#include<stack>
#include<vector>
#include<algorithm>
using namespace std;

#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())

typedef set<int> Set;
map<Set,int> IDcache; // 把集合映射成ID
vector<Set> Setcache; // 根据ID取集合

// 查找给定集合x的ID。如果找不到，分配一个新ID
int ID (Set x) {
if (IDcache.count(x)) return IDcache[x];
Setcache.push_back(x); // 添加新集合
return IDcache[x] = Setcache.size() - 1;
}

int main () {
int T;
cin >> T;
while(T--) {
stack<int> s; // 题目中的栈
int n;
cin >> n;
for(int i = 0; i < n; i++) {
string op;
cin >> op;
if (op[0] == 'P') s.push(ID(Set()));
else if (op[0] == 'D') s.push(s.top());
else {
Set x1 = Setcache[s.top()]; s.pop();
Set x2 = Setcache[s.top()]; s.pop();
Set x;
if (op[0] == 'U') set_union (ALL(x1), ALL(x2), INS(x));
if (op[0] == 'I') set_intersection (ALL(x1), ALL(x2), INS(x));
if (op[0] == 'A') { x = x2; x.insert(ID(x1)); }
s.push(ID(x));
}
cout << Setcache[s.top()].size() << endl;
}
cout << "***" << endl;
}
return 0;
}