poj 2104 K-th Number 主席树+超级详细解释 传送门:K-th Number 题目大意:给出一段数列,让你求[L,R]区间内第几大的数字! 在这里先介绍一下主席树! 如果想了解什么是主席树,就先要知道线段树,主席树就是n棵线段树,因为线段树只能维护最大值或者最小值,要想求出第二大的数字怎么办呢?两颗线段树呗!好,那么第n大呢,就可以构造n棵线段树,这样的内存是显然会爆掉的,那么怎么办呢?因为每一次更新都是更新的是从叶子节点到根节点的一条路,路的长度大约是logn,如下图红色的为…

题目链接: http://poj.org/problem?id=2104 K-th Number Time Limit: 20000MSMemory Limit: 65536K 问题描述 You are working for Macrohard company in data structures department. After failing your previous task about key insertion you were asked to write a new data…

题目链接:http://poj.org/problem?id=2104 Description You are working for Macrohard company in data structures department. After failing your previous task about key insertion you were asked to write a new data structure that would be able to return quickl…

K-th Number 题意: 给你一些数,让你求一个区间内,第k大的数是多少. 题解: 主席树第一题,看的qsc视频写的,戳戳戳 学到了unique函数,他的作用是:把相邻的重复的放到后面,返回值是放后面的第一个的迭代器. 故使用之前要排序,之后在用erase删除后面重复的,便可达到去重的目的,之后就可以离散化了. 代码: #include<iostream> #include<cstdio> #include<vector> #include<algorith…

K-th Number Time Limit: 20000MS Memory Limit: 65536K Case Time Limit: 2000MS Description You are working for Macrohard company in data structures department. After failing your previous task about key insertion you were asked to write a new data stru…

#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int MAXN = 1e5+5; int N,M; int A[MAXN]; int has[MAXN]; int htot; int get(int x){ int tt = lower_bound(has,has+htot,x)-has; return…

K-th Number Input The first line of the input file contains n --- the size of the array, and m --- the number of questions to answer (1 <= n <= 100 000, 1 <= m <= 5 000). The second line contains n different integer numbers not exceeding 109 b…

题意:给n个数,m次询问,每次询问L到R中第k小的数是哪个 算法1:划分树 #include<cstdio> #include<cstring> #include<algorithm> #include<iostream> using namespace std; ; ][mx]; int sortt[mx]; ][mx]; void build(int l,int r,int c) { if (l==r) return ; ; ; ; for (int i…

题目链接 参考HH大神的模版.对其中一些转移,还没想清楚,大体明白上是怎么回事了,划分树就是类似快排,但有点点区别的.多做几个题,慢慢理解. #include <cstdio> #include <cstring> #include <algorithm> using namespace std; #define lson l,m,rt<<1 #define rson m+1,r,rt<<1|1 #define N 100100 struct n…

划分树的基本功能是,对一个给定的数组,求区间[l,r]内的第k大(小)数. 划分树的基本思想是分治,每次查询复杂度为O(log(n)),n是数组规模. 具体原理见http://baike.baidu.com/link?url=vIUKtsKYx7byeS2KCOHUI14bt_0sdHAa9BA1VceHdGsTv5jVq36SfZgBKdaHYUGqIGvIGrE_aJtqy0D0b1fCoq 个人感觉看代码是最好的学习方法. #include <cstdio> #include <c…