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K-th Number
Time Limit: 20000MS Memory Limit: 65536K Total Submissions: 36890 Accepted: 11860 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 structure that would be able to return quickly k-th order statistics in the array segment.
That is, given an array a[1...n] of different integer numbers, your program must answer a series of questions Q(i, j, k) in the form: "What would be the k-th number in a[i...j] segment, if this segment was sorted?"
For example, consider the array a = (1, 5, 2, 6, 3, 7, 4). Let the question be Q(2, 5, 3). The segment a[2...5] is (5, 2, 6, 3). If we sort this segment, we get (2, 3, 5, 6), the third number is 5, and therefore the answer to the question is 5.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 by their absolute values --- the array for which the answers should be given.
The following m lines contain question descriptions, each description consists of three numbers: i, j, and k (1 <= i <= j <= n, 1 <= k <= j - i + 1) and represents the question Q(i, j, k).Output
For each question output the answer to it --- the k-th number in sorted a[i...j] segment.Sample Input
7 3 1 5 2 6 3 7 4 2 5 3 4 4 1 1 7 3Sample Output
5 6 3Hint
This problem has huge input,so please use c-style input(scanf,printf),or you may got time limit exceed.
1 /*************************************************************************
2 > File Name: 2104.cpp
3 > Author: Stomach_ache
4 > Mail: sudaweitong@gmail.com
5 > Created Time: 2014年08月02日 星期六 19时25分26秒
6 > Propose:
7 ************************************************************************/
8
9 #include <cmath>
10 #include <string>
11 #include <cstdio>
12 #include <vector>
13 #include <fstream>
14 #include <cstring>
15 #include <iostream>
16 #include <algorithm>
17 using namespace std;
18
19 #define lson(x) (x<<1)
20 #define rson(x) ((x<<1)|1)
21 const int maxn = 100002;
22 int n, m;
23 int a[maxn], nums[maxn];
24 vector<int> dat[maxn<<2];
25
26 void build(int o, int l, int r) {
27 if (r - l == 1) {
28 dat[o].push_back(a[l]);
29 } else {
30 int mid = (l + r) / 2;
31 build(lson(o), l, mid);
32 build(rson(o), mid, r);
33 dat[o].resize(r-l);
34 merge(dat[lson(o)].begin(), dat[lson(o)].end(), dat[rson(o)].begin(), dat[rson(o)].end(), dat[o].begin());
35 }
36 }
37
38 int query(int L, int R, int x, int o, int l, int r) {
39 if (l >= R || r <= L) return 0;
40 else if (l >= L && r <= R) return upper_bound(dat[o].begin(), dat[o].end(), x) - dat[o].begin();
41 else {
42 int md = (l + r) / 2;
43 int lc = query(L, R, x, lson(o), l, md);
44 int rc = query(L, R, x, rson(o), md, r);
45 return lc + rc;
46 }
47 }
48
49 int main(void) {
50 while (~scanf("%d %d", &n, &m)) {
51 for (int i = 0; i < n; i++) scanf("%d", a + i);
52 build(1, 0, n);
53 sort(a, a + n);
54 while (m--) {
55 int l, r, k;
56 scanf("%d %d %d", &l, &r, &k);
57 l--; r--;
58 int lb = -1, ub = n-1;
59 while (ub - lb > 1) {
60 int md = (lb + ub) / 2;
61 int c = query(l, r+1, a[md], 1, 0, n);
62 if (c >= k) ub = md;
63 else lb = md;
64 }
65 printf("%d\n", a[ub]);
66 }
67 }
68
69 return 0;
70 }
Poj 2104区间第k大（归并树）,布布扣,bubuko.com
标签：des style blog http color 使用 os strong
原文地址：http://www.cnblogs.com/Stomach-ache/p/3887394.html
