妈呀。。。clj大爷太强啦！
原来还有set_union和set_intersection这种东西。。。
于是只要把栈顶的每个元素hash一下记录到一个vector里去就好了
1 /************************************************************** 2 Problem: 1932 3 User: rausen 4 Language: C++ 5 Result: Accepted 6 Time:148 ms 7 Memory:3372 kb 8 ****************************************************************/ 9 10 #include <cstdio> 11 #include <vector> 12 #include <stack> 13 #include <algorithm> 14 15 using namespace std; 16 typedef unsigned long long ull; 17 typedef vector <ull> vec; 18 const int N = 2e3 + 5; 19 const int base = 2333; 20 21 inline ull add(const vec &v) { 22 static ull res; 23 static int i; 24 for (i = res = 0; i < v.size(); ++i) 25 res *= base, res += v[i] + 101; 26 return res; 27 } 28 29 inline void get(vec &v) { 30 sort(v.begin(), v.end()); 31 v.resize(unique(v.begin(), v.end()) - v.begin()); 32 } 33 34 int n, top; 35 vec S[N]; 36 37 int main() { 38 int i; 39 char st[15]; 40 vec a, b, c(N); 41 scanf("%d",&n); 42 for (i = 1; i <= n; ++i) { 43 scanf("%s", st + 1); 44 if (st[1] == 'P') { 45 S[++top] = vec(); 46 goto end; 47 } 48 if (st[1] == 'D') { 49 ++top, S[top] = S[top - 1]; 50 goto end; 51 } 52 a = S[top--], b = S[top--]; 53 if (st[1] == 'A') { 54 b.push_back(add(a)), get(b); 55 S[++top] = b; 56 goto end; 57 } 58 c = vec(a.size() + b.size()); 59 if (st[1] == 'U') { 60 c.resize(set_union(a.begin(), a.end(), b.begin(), b.end(), c.begin()) - c.begin()); 61 get(c), S[++top] = c; 62 goto end; 63 } 64 if (st[1] == 'I') { 65 c.resize(set_intersection(a.begin(), a.end(), b.begin(), b.end(), c.begin()) - c.begin()); 66 get(c), S[++top] = c; 67 goto end; 68 } 69 end : printf("%d ", S[top].size()); 70 } 71 return 0; 72 }