找到数组中第k小的元素：
#include <iostream>#include <algorithm>int main() { int arr[] = {9, 4, 7, 2, 5, 1, 6, 3, 8}; int k = 3; // 找第3小的元素 std::nth_element(arr, arr + k - 1, arr + 9); std::cout << "第" << k << "小的元素是：" << arr[k - 1] << std::endl; return 0;}#include <iostream>#include <algorithm>int main() { int arr[] = {9, 4, 7, 2, 5, 1, 6, 3, 8}; int k = 3; // 找第3大的元素 std::nth_element(arr, arr + 9 - k, arr + 9); std::cout << "第" << k << "大的元素是：" << arr[9 - k] << std::endl; return 0;}
