Given a data stream input of non-negative integers a₁, a₂, ..., a_n, ..., summarize the numbers seen so far as a list of disjoint intervals.

For example, suppose the integers from the data stream are 1, 3, 7, 2, 6, ..., then the summary will be:

[1, 1]
[1, 1], [3, 3]
[1, 1], [3, 3], [7, 7]
[1, 3], [7, 7]
[1, 3], [6, 7]

Follow up:
What if there are lots of merges and the number of disjoint intervals are small compared to the data stream's size?

Credits:
Special thanks to @yunhong for adding this problem and creating most of the test cases.

這道題說有個資料流每次提供一個數字，然後讓我們組成一系列分離的區間，這道題跟之前那道Insert Interval很像，思路也很像，每進來一個新的數字val，我們都生成一個新的區間[val, val]，然後將其插入到當前的區間裡，注意分情況討論，無重疊，相鄰，和有重疊分開討論處理，參見程式碼如下:

class SummaryRanges {
public:
    /** Initialize your data structure here. */
    SummaryRanges() {}
    
    void addNum(int val) {
        Interval cur(val, val);
        vector<Interval> res;
        int pos = 0;
        for (auto a : v) {
            if (cur.end + 1 < a.start) {
                res.push_back(a);
            } 
 
else if (cur.start > a.end + 1) {
                res.push_back(a);
                ++pos;
            } else {
                cur.start = min(cur.start, a.start);
                cur.end = max(cur.end, a.end);
            }
        }
        res.insert(res.begin() + pos, cur);
        v = res;
    }
    
    vector<Interval> getIntervals() {
        return v;    
    }
    
private:
    vector<Interval> v;
};

類似題目：

參考資料: