[LeetCode] 56. Merge Intervals 解题思路

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

问题：给定一个区间集合，整合所有重叠的区间。

对区间集合按照 start 来排序，然后根据 intervals[i].start 和 res.lastElement.end 来整合即可。

    int static comp(Interval t1, Interval t2){
        int res = (t2.start > t1.start);
        return res;
    }

    vector<Interval> merge(vector<Interval>& intervals) {
        
        vector<Interval> vt;
    
        if (intervals.size() == 0) {
            return vt;
        }
            
        std::sort(intervals.begin(), intervals.end(), comp);
                
        vt.push_back(intervals[0]);
        
        for (int i = 1 ; i < intervals.size(); i++) {
            
            if (intervals[i].start <= vt.back().end) {
                vt.back().end = max( vt.back().end, intervals[i].end);
            }else{
                vt.push_back(intervals[i]);
            }
        }
    
        return vt;
        
    }