Given an nonnegative integer array, find a subarray where the sum of numbers is k.
Your code should return the index of the first number and the index of the last number.Example
Given [1, 4, 20, 3, 10, 5], sum k = 33, return [2, 4].

#include <iostream>
#include <vector>
#include <map>using namespace std;class Solution {
public:/*** @param nums: A list of integers* @return: A list of integers includes the index of the first number*          and the index of the last number*/vector<int> subarraySum(vector<int> nums, int k){vector<int> result;// curr_sum for the first item, index for the second item// unordered_map<int, int> hash;map<int, int> hash;hash[0] = 0;int curr_sum = 0;for (int i = 0; i != nums.size(); ++i) {curr_sum += nums[i];if (hash.find(curr_sum - k) != hash.end()) {result.push_back(hash[curr_sum - k]);result.push_back(i);return result;} else {hash[curr_sum] = i + 1;}}return result;}
};int main(int argc, char *argv[])
{int int_array1[] = {1, 4, 20, 3, 10, 5};int int_array2[] = {1, 4, 0, 0, 3, 10, 5};vector<int> vec_array1;vector<int> vec_array2;for (int i = 0; i != sizeof(int_array1) / sizeof(int); ++i) {vec_array1.push_back(int_array1[i]);}for (int i = 0; i != sizeof(int_array2) / sizeof(int); ++i) {vec_array2.push_back(int_array2[i]);}Solution solution;vector<int> result1 = solution.subarraySum(vec_array1, 33);vector<int> result2 = solution.subarraySum(vec_array2, 7);cout << "result1 = [" << result1[0] << " ," << result1[1] << "]" << endl;cout << "result2 = [" << result2[0] << " ," << result2[1] << "]" << endl;return 0;
}

result1 = [2 ,4]
result2 = [1 ,4]

#include <iostream>
#include <vector>
#include <map>using namespace std;class Solution {
public:/*** @param nums: A list of integers* @return: A list of integers includes the index of the first number*          and the index of the last number*/vector<int> subarraySum2(vector<int> &nums, int k){vector<int> result;int left_index = 0, curr_sum = 0;for (int i = 0; i != nums.size(); ++i) {while (curr_sum > k) {curr_sum -= nums[left_index];++left_index;}if (curr_sum == k) {result.push_back(left_index);result.push_back(i - 1);return result;}curr_sum += nums[i];}return result;}
};int main(int argc, char *argv[])
{int int_array1[] = {1, 4, 20, 3, 10, 5};int int_array2[] = {1, 4, 0, 0, 3, 10, 5};vector<int> vec_array1;vector<int> vec_array2;for (int i = 0; i != sizeof(int_array1) / sizeof(int); ++i) {vec_array1.push_back(int_array1[i]);}for (int i = 0; i != sizeof(int_array2) / sizeof(int); ++i) {vec_array2.push_back(int_array2[i]);}Solution solution;vector<int> result1 = solution.subarraySum2(vec_array1, 33);vector<int> result2 = solution.subarraySum2(vec_array2, 7);cout << "result1 = [" << result1[0] << " ," << result1[1] << "]" << endl;cout << "result2 = [" << result2[0] << " ," << result2[1] << "]" << endl;return 0;
}

result1 = [2 ,4]
result2 = [1 ,4]