和为定值的两个数组元素

在数组中找到和为定值的两个数，返回数组下标。
这个题目就是一个排序的问题，但是不能改变数组，用快排的方式存储数组的索引值即可，上代码。

#include <iostream>#include <cstdlib>#include <cstring>#include <vector>using namespace std;void quicksort_index(int *arr, int *index, int low, int high){    if (low >= high)        return;    int i = low;    int j = high;    int tmp = index[j];    int val = arr[index[j]];    while (i < j)    {        while (i < j && arr[index[i]] <= val)            i++;        index[j] = index[i];        while (i < j && arr[index[j]] > val)            j--;        index[i] = index[j];    }    index[i] = tmp;    quicksort_index(arr, index, low, i-1);    quicksort_index(arr, index, i+1, high);}void get_two_sum_index(int *arr, int *index_arr, int len, int two_sum, std::vector<int> &ivec){    int start_index = 0;    int end_index = len;    int i = 0;    int j = 0;    ivec.clear();    while (start_index < end_index)    {        i = index_arr[start_index];        j = index_arr[end_index];        if (two_sum == arr[i] + arr[j]) {            ivec.push_back(i);            ivec.push_back(j);            start_index++;            end_index--;        } else if (two_sum > arr[i] + arr[j]) {            start_index++;        } else {            end_index--;        }    }}int main(int argc, char *argv[]){    //int arr[] = {1, -2, 3, 10, -4, 7, 2, -5};    int arr[] = {102, 21, 39, 210, 94, 72, 2, 5, 167};    int len = sizeof(arr) / sizeof(int);    std::cout << "array data" << std::endl;    int *index_arr = new int[len];    int i = 0;    for (i = 0; i < len; i++)    {        std::cout << arr[i] << " ";        index_arr[i] = i;    }    std::cout << std::endl;    quicksort_index(arr, index_arr, 0, len-1);    for (i = 0; i < len; i++)    {        std::cout << arr[i] << " ";    }    std::cout << std::endl;    for (i = 0; i < len; i++)    {        std::cout << arr[index_arr[i]] << " ";    }    std::cout << std::endl;    int two_sum = 111;    std::cout << "to get two sum: " << two_sum << std::endl;    std::vector<int> ivec;    get_two_sum_index(arr, index_arr, len-1, two_sum, ivec);    std::vector<int>::iterator iter;    int min_val;    int max_val;    for (iter = ivec.begin(); iter != ivec.end(); iter++)    {        std::cout << "[min_index, max_index]: " << *iter << ", ";        min_val = arr[*iter];        iter++;        max_val = arr[*iter];        std::cout << *iter << std::endl;        std::cout << "[min_val, max_val]: " << min_val << " " << max_val << std::endl;    }    return 0;}