【树链剖分】有序剖分模板

 

struct seg {
    int l, r;
    int flag;
    int id;
}s[N];
int split(int x, int y) {
    int cnt = 0;
    int flag=0;
    int fx = top[x], fy = top[y];
    while (fx != fy) {
        if (dep[fx] < dep[fy]) {
            swap(fx, fy);
            swap(x, y);
            flag=!flag;
        }
        s[cnt].flag=flag,s[cnt].id=cnt;
        s[cnt].l = dfn[fx],s[cnt++].r = dfn[x];
    
        x = fa[fx];
        fx = top[x];
    }
    if (dfn[x] > dfn[y]){
        swap(x, y);
        flag=!flag;
    }
    s[cnt].flag=!flag,s[cnt].id=cnt;
    s[cnt].l = dfn[x], s[cnt++].r = dfn[y];
    return cnt;
}

bool cmp(seg a,seg b){
    if(a.flag==b.flag){
        if(a.flag){
            return a.id>b.id;
        }
        else{
            return a.id<b.id;
        }
    }
    else return a.flag<b.flag;
}