题目描述

blablabla

样例

blablabla

C++ 代码

LL merge(vector<Segment>&q)
{
    vector<Segment>w;
    sort(q.begin(),q.end());
    LL res=0;
    for(int i=0;i<q.size();)
    {
        int j=i;
        while(j<q.size()&&q[j].k==q[i].k) j++;

        int st=-2e9,ed=st-1;
        for(int k=i;k<j;k++)
        {
            if(q[k].l>ed)
            {
                res+=ed-st+1;
                if(st!=-2e9) w.push_back({q[i].k,st,ed});
                st=q[k].l,ed=q[k].r;
            }
            else ed=max(ed,q[k].r);
        }
        if(st!=-2e9) w.push_back({q[i].k,st,ed});
        res+=ed-st+1;

        i=j;
    }
    q=w;
    return res;
}

不懂if(st!=-2e9) w.push_back({q[i].k,st,ed});这里啥意思