CF981G 线段树 set

上次模拟赛还有一道题忘记发了….
这个题还是有点难想
仔细读题 发现修改的每个区间只和修改的颜色有关
于是对于每一种颜色开一个set 存它尚未覆盖的区间
初始化每个颜色都包含$[1, n]$这个区间
每次修改的时候把整个区间$×2$
set中有相交的区间拆成$[l, L]$和$[r, R]$并$×inv_2$和$+ 1$就可以了

#include<bits/stdc++.h>
#define For(i, a, b) for(register int i = a; i <= b; ++ i)
#define PII pair<int, int> 
#define mp make_pair
#define X first
#define Y second

using namespace std;
typedef long long ll;

const int maxn = 2e5 + 10, mod = 998244353;
int n, m, inv;
set<PII> T[maxn];
set<PII>::iterator it, l, r;

int qpow(ll a, int x)
{
    ll ret = 1;
    while(x)
    {
        if(x & 1) 
            (ret *= a) %= mod;
        x >>= 1;
        (a *= a) %= mod;
    }
    return ret;
}

/*{{{*/
namespace Segment_Tree
{
#define ls (bh << 1)
#define rs (bh << 1 | 1)
#define mid ((l + r) >> 1)
    ll s[maxn << 2], lazc[maxn << 2], lazj[maxn << 2];
    void pushup(int bh)
    {
        s[bh] = (s[ls] + s[rs]) % mod;
    }
    void pushdown(int bh, int l, int r)
    {
        if(lazc[bh] ^ 1)
        {   
            (lazc[ls] *= lazc[bh]) %= mod, (lazc[rs] *= lazc[bh]) %= mod;
            (lazj[ls] *= lazc[bh]) %= mod, (lazj[rs] *= lazc[bh]) %= mod;
            (s[ls] *= lazc[bh]) %= mod, (s[rs] *= lazc[bh]) %= mod;
            lazc[bh] = 1;
        }
        if(lazj[bh])
        {
            (lazj[ls] += lazj[bh]) %= mod, (lazj[rs] += lazj[bh]) %= mod;
            (s[ls] += 1ll * (mid - l + 1) * lazj[bh]) %= mod;
            (s[rs] += 1ll * (r - mid) * lazj[bh]) %= mod;
            lazj[bh] = 0;
        }
    }
    void mulupdate(int bh, int l, int r, int x, int y, int z)
    {
        if(x <= l && r <= y)
        {
            (s[bh] *= z) %= mod;
            (lazj[bh] *= z) %= mod;
            (lazc[bh] *= z) %= mod;
        }
        else
        {
            pushdown(bh, l, r);
            if(x <= mid) mulupdate(ls, l, mid, x, y, z);
            if(y > mid) mulupdate(rs, mid + 1, r, x, y, z);
            pushup(bh);
        }
    }
    void addupdate(int bh, int l, int r, int x, int y, int z)
    {
        if(x <= l && r <= y)
        {
            (s[bh] += 1ll * (r - l + 1) * z) %= mod;
            (lazj[bh] += z) %= mod;
        }
        else
        {
            pushdown(bh, l, r);
            if(x <= mid) addupdate(ls, l, mid, x, y, z);
            if(y > mid) addupdate(rs, mid + 1, r, x, y, z);
            pushup(bh);
        }
    }
    int query(int bh, int l, int r, int x, int y)
    {
        ll res = 0;
        if(x <= l && r <= y)
            (res += s[bh]) %= mod;
        else
        {
            pushdown(bh, l, r);
            if(x <= mid) (res += query(ls, l, mid, x, y)) %= mod;
            if(y > mid) (res += query(rs, mid + 1, r, x, y)) %= mod;
        }
        return res;
    }
}
/*}}}*/


void split(int x, int z)
{
    it = T[z].lower_bound(mp(x, x));
    if(it != T[z].begin())
    {
        -- it;
        if((*it).Y >= x)
        {
            T[z].insert(mp(x, (*it).Y));
            if((it->X)<=x-1)T[z].insert(mp((*it).X, x - 1));
            T[z].erase(it);
        }
    }
}

int main()
{
    freopen("multiset.in", "r", stdin);
    freopen("multiset.out", "w", stdout);
    int op, x, y, z;
    scanf("%d%d", &n, &m);
    inv = qpow(2, mod - 2);
    For(i, 1, n)
        T[i].insert(mp(1, n));
    For(i, 1, n << 2)
        Segment_Tree::lazc[i] = 1;
    for(; m -- ; )
    {
        scanf("%d%d%d", &op, &x, &y);
        if(op == 1) 
        {
            scanf("%d", &z);
            Segment_Tree::mulupdate(1, 1, n, x, y, 2);  
            split(x, z), split(y + 1, z);
            r = T[z].end();
            while(true)
            {
                it = T[z].lower_bound(mp(x, x));
                if(it == r || (*it).X > y)
                    break;
                Segment_Tree::mulupdate(1, 1, n, (*it).X, (*it).Y, inv);
                Segment_Tree::addupdate(1, 1, n, (*it).X, (*it).Y, 1);
                T[z].erase(it);
            }
        }
        else
            printf("%d\n", Segment_Tree::query(1, 1, n, x, y));
    }
    return 0;
}