POJ 2104 - K-th Number

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 31 5 2 6 3 7 42 5 34 4 11 7 3

Sample Output

563

题意：在给出 m 个数字和 n 个操作次数，每个操作次数给出3个数a，b，c，求出在区间 [a, b] 中第 c 大的数。

每个数字不但给他们数值，也给出序号，每次操作时从小到大遍历，遇到区间内的 c-1 ，直到 c 减到0即是答案。

#include <cstdio>#include <algorithm>using namespace std;struct node{    int n, no;};node num[1000000 + 5];int cmp(node a, node b){    return a.n < b.n;}int main(){    int m, n;    scanf("%d%d", &m, &n);    for (int i = 0; i < m; ++i)    {        scanf("%d", &num[i].n);        num[i].no = i;    }    sort(num, num+m, cmp);    for (int i = 0; i < n; ++i)    {        int from, to, sym;        scanf("%d%d%d", &from, &to, &sym);        from--;        to--;        for (int j = 0; j < m; ++j)        {            if (num[j].no >= from && num[j].no <= to)                sym--;            if (sym == 0)            {                printf("%d\n", num[j].n);                break;            }        }    }    return 0;}