README_EN.md

352. Data Stream as Disjoint Intervals

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Description

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

Implement the SummaryRanges class:

• SummaryRanges() Initializes the object with an empty stream.
• void addNum(int val) Adds the integer val to the stream.
• int[][] getIntervals() Returns a summary of the integers in the stream currently as a list of disjoint intervals [starti, endi].

 

Example 1:

Input
["SummaryRanges", "addNum", "getIntervals", "addNum", "getIntervals", "addNum", "getIntervals", "addNum", "getIntervals", "addNum", "getIntervals"]
[[], [1], [], [3], [], [7], [], [2], [], [6], []]
Output
[null, null, [[1, 1]], null, [[1, 1], [3, 3]], null, [[1, 1], [3, 3], [7, 7]], null, [[1, 3], [7, 7]], null, [[1, 3], [6, 7]]]

Explanation
SummaryRanges summaryRanges = new SummaryRanges();
summaryRanges.addNum(1);      // arr = [1]
summaryRanges.getIntervals(); // return [[1, 1]]
summaryRanges.addNum(3);      // arr = [1, 3]
summaryRanges.getIntervals(); // return [[1, 1], [3, 3]]
summaryRanges.addNum(7);      // arr = [1, 3, 7]
summaryRanges.getIntervals(); // return [[1, 1], [3, 3], [7, 7]]
summaryRanges.addNum(2);      // arr = [1, 2, 3, 7]
summaryRanges.getIntervals(); // return [[1, 3], [7, 7]]
summaryRanges.addNum(6);      // arr = [1, 2, 3, 6, 7]
summaryRanges.getIntervals(); // return [[1, 3], [6, 7]]

 

Constraints:

• 0 <= val <= 104
• At most 3 * 104 calls will be made to addNum and getIntervals.

 

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

Solutions

Python3

from sortedcontainers import SortedDict

class SummaryRanges:

    def __init__(self):
        self.mp = SortedDict()

    def addNum(self, val: int) -> None:
        n = len(self.mp)
        ridx = self.mp.bisect_right(val)
        lidx = n if ridx == 0 else ridx - 1
        keys = self.mp.keys()
        values = self.mp.values()
        if lidx != n and ridx != n and values[lidx][1] + 1 == val and values[ridx][0] - 1 == val:
            self.mp[keys[lidx]][1] = self.mp[keys[ridx]][1]
            self.mp.pop(keys[ridx])
        elif lidx != n and val <= values[lidx][1] + 1:
            self.mp[keys[lidx]][1] = max(val, self.mp[keys[lidx]][1])
        elif ridx != n and val >= values[ridx][0] - 1:
            self.mp[keys[ridx]][0] = min(val, self.mp[keys[ridx]][0])
        else:
            self.mp[val] = [val, val]

    def getIntervals(self) -> List[List[int]]:
        return list(self.mp.values())


# # Your SummaryRanges object will be instantiated and called as such:
# # obj = SummaryRanges()
# # obj.addNum(val)
# # param_2 = obj.getIntervals()

Java

class SummaryRanges {
    private TreeMap<Integer, int[]> mp;

    public SummaryRanges() {
        mp = new TreeMap<>();
    }

    public void addNum(int val) {
        Integer l = mp.floorKey(val);
        Integer r = mp.ceilingKey(val);
        if (l != null && r != null && mp.get(l)[1] + 1 == val && mp.get(r)[0] - 1 == val) {
            mp.get(l)[1] = mp.get(r)[1];
            mp.remove(r);
        } else if (l != null && val <= mp.get(l)[1] + 1) {
            mp.get(l)[1] = Math.max(val, mp.get(l)[1]);
        } else if (r != null && val >= mp.get(r)[0] - 1) {
            mp.get(r)[0] = Math.min(val, mp.get(r)[0]);
        } else {
            mp.put(val, new int[]{val, val});
        }
    }

    public int[][] getIntervals() {
        int[][] res = new int[mp.size()][2];
        int i = 0;
        for (int[] range : mp.values()) {
            res[i++] = range;
        }
        return res;
    }
}

/**
 * Your SummaryRanges object will be instantiated and called as such:
 * SummaryRanges obj = new SummaryRanges();
 * obj.addNum(val);
 * int[][] param_2 = obj.getIntervals();
 */

C++

class SummaryRanges {
private:
    map<int, vector<int>> mp;
public:
    SummaryRanges() {

    }

    void addNum(int val) {
        auto r = mp.upper_bound(val);
        auto l = r == mp.begin() ? mp.end() : prev(r);
        if (l != mp.end() && r != mp.end() && l->second[1] + 1 == val && r->second[0] - 1 == val)
        {
            l->second[1] = r->second[1];
            mp.erase(r);
        }
        else if (l != mp.end() && val <= l->second[1] + 1) l->second[1] = max(val, l->second[1]);
        else if (r != mp.end() && val >= r->second[0] - 1) r->second[0] = min(val, r->second[0]);
        else mp[val] = {val, val};
    }

    vector<vector<int>> getIntervals() {
        vector<vector<int>> res;
        for (auto& range : mp) res.push_back(range.second);
        return res;
    }
};

/**
 * Your SummaryRanges object will be instantiated and called as such:
 * SummaryRanges* obj = new SummaryRanges();
 * obj->addNum(val);
 * vector<vector<int>> param_2 = obj->getIntervals();
 */

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