Leetcode 715. Range Module

Problem:

A Range Module is a module that tracks ranges of numbers. Your task is to design and implement the following interfaces in an efficient manner.

 

• addRange(int left, int right) Adds the half-open interval [left, right), tracking every real number in that interval. Adding an interval that partially overlaps with currently tracked numbers should add any numbers in the interval [left, right) that are not already tracked.
• queryRange(int left, int right) Returns true if and only if every real number in the interval [left, right) is currently being tracked.
• removeRange(int left, int right) Stops tracking every real number currently being tracked in the interval [left, right).

Example 1:

addRange(10, 20): null
removeRange(14, 16): null
queryRange(10, 14): true (Every number in [10, 14) is being tracked)
queryRange(13, 15): false (Numbers like 14, 14.03, 14.17 in [13, 15) are not being tracked)
queryRange(16, 17): true (The number 16 in [16, 17) is still being tracked, despite the remove operation)

Note:

• A half open interval [left, right) denotes all real numbers left <= x < right.
• 0 < left < right < 10^9 in all calls to addRange, queryRange, removeRange.
• The total number of calls to addRange in a single test case is at most 1000.
• The total number of calls to queryRange in a single test case is at most 5000.
• The total number of calls to removeRange in a single test case is at most 1000.

Solution:

　　Leetcode 57. Insert Interval的升级版，addRange函数一样，removeRange函数如果segments[i]和要删除的部分没有重叠，则添加到结果集中，如果有重叠则分为两种情况：

　　1. ---------  segments[i]

　　        ---------

　　left如果大于segments[i]的first，则添加（segments[i].first，left）

　　2.      ---------  segments[i]

　　    ---------

　　right如果小于segments[i]的second，则添加（right，segments[i].second）

　　对于queryRange函数，简单的二分查找即可

Code:

class RangeModule {
public:
    RangeModule() {
        
    }
    
    void addRange(int left, int right) {
        auto iter = segments.begin();
        while(iter != segments.end() && (*iter).first < left)
            iter++;
        segments.insert(iter,make_pair(left,right));
        vector<pair<int,int>> result;
        for(int i = 0;i != segments.size();++i){
            if(result.empty() || segments[i].first > result.back().second)
                result.push_back(segments[i]);
            else{
                result.back().second = max(result.back().second,segments[i].second);
            }
        }
        segments = result;
    }
    
    bool queryRange(int left, int right) {
        if(segments.size() == 0 || left < segments[0].first){
            return false;
        }
        int start = 0;
        int end = segments.size()-1;
        while(start < end){
            int pivot = start+(end-start+1)/2;
            if(segments[pivot].first > left)
                end = pivot-1;
            else
                start = pivot;
        }
        return segments[start].second >= right;
    }
    
    void removeRange(int left, int right) {
        vector<pair<int,int>> result;
        for(int i = 0;i != segments.size();++i){
            if(segments[i].second <= left || segments[i].first >= right)
                result.push_back(segments[i]);
            else {
                if(segments[i].first < left)
                    result.push_back(make_pair(segments[i].first,left));
                if(segments[i].second > right)
                    result.push_back(make_pair(right,segments[i].second));
            }
        }
        segments = result;
    }
private:
    vector<pair<int,int>> segments;
};

/**
 * Your RangeModule object will be instantiated and called as such:
 * RangeModule obj = new RangeModule();
 * obj.addRange(left,right);
 * bool param_2 = obj.queryRange(left,right);
 * obj.removeRange(left,right);
 */