H - Black Box
Time Limit:1000MS Memory Limit:10000KB 64bit IO Format:%I64d
& %I64u
Description
Our Black Box represents a primitive database. It can save an integer array and has a special i variable. At the initial moment Black Box is empty and i equals 0. This Black Box processes a sequence of commands (transactions). There are two types of transactions:
ADD (x): put element x into Black Box;
GET: increase i by 1 and give an i-minimum out of all integers containing in the Black Box. Keep in mind that i-minimum is a number located at i-th place after Black Box elements sorting by non- descending.
Let us examine a possible sequence of 11 transactions:
Example 1
It is required to work out an efficient algorithm which treats a given sequence of transactions. The maximum number of ADD and GET transactions: 30000 of each type.
Let us describe the sequence of transactions by two integer arrays:
1. A(1), A(2), ..., A(M): a sequence of elements which are being included into Black Box. A values are integers not exceeding 2 000 000 000 by their absolute value, M <= 30000. For the Example we have A=(3, 1, -4, 2, 8, -1000, 2).
2. u(1), u(2), ..., u(N): a sequence setting a number of elements which are being included into Black Box at the moment of first, second, ... and N-transaction GET. For the Example we have u=(1, 2, 6, 6).
The Black Box algorithm supposes that natural number sequence u(1), u(2), ..., u(N) is sorted in non-descending order, N <= M and for each p (1 <= p <= N) an inequality p <= u(p) <= M is valid. It follows from the fact that for the p-element of our u sequence we perform a GET transaction giving p-minimum number from our A(1), A(2), ..., A(u(p)) sequence.
ADD (x): put element x into Black Box;
GET: increase i by 1 and give an i-minimum out of all integers containing in the Black Box. Keep in mind that i-minimum is a number located at i-th place after Black Box elements sorting by non- descending.
Let us examine a possible sequence of 11 transactions:
Example 1
N Transaction i Black Box contents after transaction Answer (elements are arranged by non-descending) 1 ADD(3) 0 3 2 GET 1 3 3 3 ADD(1) 1 1, 3 4 GET 2 1, 3 3 5 ADD(-4) 2 -4, 1, 3 6 ADD(2) 2 -4, 1, 2, 3 7 ADD(8) 2 -4, 1, 2, 3, 8 8 ADD(-1000) 2 -1000, -4, 1, 2, 3, 8 9 GET 3 -1000, -4, 1, 2, 3, 8 1 10 GET 4 -1000, -4, 1, 2, 3, 8 2 11 ADD(2) 4 -1000, -4, 1, 2, 2, 3, 8
It is required to work out an efficient algorithm which treats a given sequence of transactions. The maximum number of ADD and GET transactions: 30000 of each type.
Let us describe the sequence of transactions by two integer arrays:
1. A(1), A(2), ..., A(M): a sequence of elements which are being included into Black Box. A values are integers not exceeding 2 000 000 000 by their absolute value, M <= 30000. For the Example we have A=(3, 1, -4, 2, 8, -1000, 2).
2. u(1), u(2), ..., u(N): a sequence setting a number of elements which are being included into Black Box at the moment of first, second, ... and N-transaction GET. For the Example we have u=(1, 2, 6, 6).
The Black Box algorithm supposes that natural number sequence u(1), u(2), ..., u(N) is sorted in non-descending order, N <= M and for each p (1 <= p <= N) an inequality p <= u(p) <= M is valid. It follows from the fact that for the p-element of our u sequence we perform a GET transaction giving p-minimum number from our A(1), A(2), ..., A(u(p)) sequence.
Input
Input contains (in given order): M, N, A(1), A(2), ..., A(M), u(1), u(2), ..., u(N). All numbers are divided by spaces and (or) carriage return characters.
Output
Write to the output Black Box answers sequence for a given sequence of transactions, one number each line.
Sample Input
7 4 3 1 -4 2 8 -1000 2 1 2 6 6
Sample Output
3 3 1 2
做法,定义两个优先队列。以大优先的p1。以小优先的p2,假设要求的是第x小的值。p1中存下(x-1)个小值,那么第x个就是p2的队首,在求第一个小的值,p1为空,求完第一个小的值后,将p2的队首放入p1,再来求第二小的值。读取给出的数(a)时,假设a大于p1的队首,那么a放入p2。否则。将a放入p1,p1的队首放入p2,保证p1的个数均比p2小。且为(x-1)个,读取完数后p2的队首就是第x小的数,输出。再把p2的队首放入p1,运行之前的操作,得到下一个要求的最小值。
用两个优先队列。分开总体的数组,得到第x小值
#include <cstdio> #include <cstring> #include <queue> #include <vector> #include <algorithm> using namespace std; #define LL __int64 priority_queue <LL> p1 ; priority_queue <LL,vector<LL>,greater<LL> > p2 ; LL a[6000000] ; int main() { int i , j , n , m , x ; LL temp ; while(scanf("%d %d", &n, &m)!=EOF) { while( !p1.empty() ) p1.pop(); while( !p2.empty() ) p2.pop() ; for(i = 1 ; i <= n ; i++) scanf("%I64d", &a[i]); i = 1 ; while(m--) { scanf("%d", &x); for( ; i <= x ; i++) { if( p1.empty() || p1.top() < a[i] ) p2.push(a[i]); else { p1.push(a[i]); temp = p1.top() ; p1.pop() ; p2.push(temp); } } temp = p2.top(); p2.pop() ; printf("%d ", temp); p1.push(temp); } } return 0; }