56. Merge Intervals
- kind of opposite approach of non overlapping Intervals
- sorted according to first index.
- if overlapping noticed we immediately deleted that part kept the previous part with extended version.
- extended version means the
end value is extended by the max of both intervals.
implementation
```cpp
vector<pair<int, int>> arr;
vector<vector> ans;
for (const auto& i: intervals)
arr.push_back({i[0], i[1]});
sort(arr.begin(), arr.end());
int curr = 0;
for (int i = 1; i < arr.size(); i++) {
if (arr[i].first <= arr[curr].second) {
arr[curr].second = max(arr[i].second, arr[curr].second);
arr[i].first = -1;
arr[i].second = -1;
}
else {
curr = i;
}
}
for (const auto& i: arr) if (i.first != -1)
ans.push_back({i.first, i.second});
return ans;
}
```
</details>