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| The kth great number | ||||||
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| Description | ||||||
| Xiao Ming and Xiao Bao are playing a simple Numbers game. In a round Xiao Ming can choose to write down a number, or ask Xiao Bao what the kth great number is. Because the number written by Xiao Ming is too much, Xiao Bao is feeling giddy. Now, try to help Xiao Bao. | ||||||
| Input | ||||||
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There are several test cases. For each test case, the first line of input contains two positive integer n, k. Then n lines follow. If Xiao Ming choose to write down a number, there will be an " I" followed by a number that Xiao Ming will write down. If Xiao Ming choose to ask Xiao Bao, there will be a "Q", then you need to output the kth great number.
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| Output | ||||||
| The output consists of one integer representing the largest number of islands that all lie on one line. | ||||||
| Sample Input | ||||||
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8 3 I 1 I 2 I 3 Q I 5 Q I 4 Q
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| Sample Output | ||||||
| 1 2 3 | ||||||
| Source | ||||||
| The 36th ACM/ICPC Asia Regional Dalian Site —— Online Contest |
本题考查对priority_queue的使用
priority_queue 对于基本类型的使用方法相对简单。他的模板声明带有三个参数:
priority_queue<Type, Container, Functional>
其中Type 为数据类型， Container 为保存数据的容器，Functional 为元素比较方式。
Container 必须是用数组实现的容器，比如 vector, deque 但不能用 list.
STL里面默认用的是 vector. 比较方式默认用 operator< , 所以如果你把后面俩个参数缺省的话，
优先队列就是大顶堆，队头元素最大。如果要用到小顶堆，则一般要把模板的三个参数都带进去。
STL里面定义了一个仿函数 greater<>，对于基本类型可以用这个仿函数声明小顶堆
以上这段话来自大神博客：http://www.cnblogs.com/flyoung2008/articles/2136485.html
代码：
#include<cstdio> #include<cmath> #include<queue> #include<iostream> using namespace std; priority_queue<int> a,b; int main() { int h,n,k,x; char m; while(~scanf("%d%d",&n,&k)) { while(!a.empty()) { a.pop(); } while(n--) { getchar(); scanf("%c",&m); if(m==‘I‘) { scanf("%d",&x); a.push(x); } else if(m==‘Q‘) { h=k-1; b=a; while(h--) { b.pop(); } printf("%d\n",b.top()); // getchar(); // printf("%d\n",a.top()); } } } return 0; }
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原文地址：http://www.cnblogs.com/beige1315402725/p/4977222.html
