给定一个数列a1,a2,a3,...,an和m个三元组表示的查询，对于每个查询(i，j，k)，输出ai，ai+1，...，aj的升序排列中第k个数。

给定一个数列a1,a2,a3,...,an和m个三元组表示的查询，对于每个查询(i，j，k)，输出ai，ai+1，...，aj的升序排列中第k个数。

#include <iostream>
using namespace std;
#define SIZE 20
#define M 3
typedef struct Elem {
	int i, j;
	int k;
} ELEM; /* 表示一个元素的三元组结构 */

int getMedian(int* arr, int low, int high) {
	int mid = low + ((high - low) >> 1);

	if (arr[mid] > arr[high]) {
		swap(arr[mid], arr[high]);
	}
	if (arr[low] > arr[high]) {
		swap(arr[low], arr[high]);
	}
	if (arr[mid] > arr[low]) {
		swap(arr[low], arr[mid]);
	}

	return arr[low];
}

int findThMin(int* arr, int low, int high, int k) {
	int pivot = getMedian(arr, low, high);

	int lowTmp = low;
	int highTmp = high;

	while (lowTmp < highTmp) {
		while (lowTmp < highTmp && arr[highTmp] > pivot) {
			highTmp--;
		}
		arr[lowTmp] = arr[highTmp];

		while (lowTmp < highTmp && arr[lowTmp] < pivot) {
			lowTmp++;
		}
		arr[highTmp] = arr[lowTmp];
	}

	arr[lowTmp] = pivot;

	if (k == lowTmp) {
		return arr[lowTmp];
	} else if (k < lowTmp) {
		return findThMin(arr, low, lowTmp - 1, k);
	} else {
		return findThMin(arr, lowTmp + 1, high, k);
	}
}

int* getSubArray(int* arr, int begin, int end) {
	int* tmp = new int[end - begin + 1];

	for (int i = 0, j = begin; j <= end; ++i, j++) {
		tmp[i] = arr[j];
	}
	return tmp;
}

int main() {
	Elem* elem = new Elem();
	elem->i = 4;
	elem->j = 9;
	elem->k = 3;

	Elem* elem2 = new Elem();
	elem2->i = 2;
	elem2->j = 8;
	elem2->k = 6;

	Elem* elem3 = new Elem();
	elem3->i = 1;
	elem3->j = 6;
	elem3->k = 5;

	Elem *elems[M] = { elem, elem2, elem3 };

	int* arr = new int[SIZE];
	srand(unsigned(time(0)));
	for (int i = 0; i < SIZE; i++) {
		arr[i] = rand() * RAND_MAX + rand();
	}

	for (int i = 0; i < M; ++i) {
//		cout << elems[i]->k << endl;
		//获取指定子数组
		int* tmp = getSubArray(arr, elems[i]->i - 1, elems[i]->j - 1);

		/*cout << "before data set:" << endl;
		 for (int k = 0; k <= elems[i]->j - elems[i]->i; ++k) {
		 cout << tmp[k] << endl;
		 }*/

		//在规定的数组内取得第几个最小的元素
		int data = findThMin(tmp, 0, elems[i]->j - elems[i]->i,
				elems[i]->k - 1);
		cout << elems[i]->k << " th min data:" << data << endl;

		cout << "after data set:" << endl;
		for (int k = 0; k <= elems[i]->j - elems[i]->i; ++k) {
			cout << tmp[k] << endl;
		}
	}

	return 0;
}