CareerCup Find the biggest interval that has all its members in list in O(n)

Given a list of integers, find out the biggest interval that has all its members in the given list. e.g. given list 1, 7, 4, 6, 3, 10, 2 then answer would be [1, 4]. Develop algorithm and write code for this

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What is biggest interval? It means the longest consecutive integers. Take the above example, 1, 2, 3, 4 are members of the list.

#include<iostream>#include<stdio.h>#include<stack>#include<vector>#include<string>#include<unordered_set>#include<unordered_map>#include<set>#include<queue>#include<map>using namespace std;class Solution { public:  void largestRange(vector<int>& lst, vector<int>& range) {    unordered_set<int> table;    range[0] = 0;    range[1] = -1;    int size = lst.size(), i, j, cur, a, b;    for (i = 0; i < size; ++i)       table.insert(lst[i]);       for (unordered_set<int>::iterator it = table.begin(); table.size() > 0; it = table.begin()) {      cur = *it;      table.erase(it);      for (i = cur + 1; table.size() > 0; ++i) {        if (table.find(i) == table.end())          break;        table.erase(i);      }      b = i - 1;      for (j = cur - 1; table.size() > 0; --j) {        if (table.find(j) == table.end())          break;        table.erase(j);      }      a = j + 1;  if (b - a > range[1] - range[0]) {    range[1] = b;    range[0] = a;      }    }  }};int main() {  Solution s;  int a[] = {1, 7, 4, 6, 3, 10, 2};  vector<int> v(a, a + 7);  vector<int> range(2);  s.largestRange(v, range);  cout<<range[0]<<" "<<range[1]<<endl;    return 0;}