牛客 - 1221E - Forsaken的数列 = 无旋Treap

https://ac.nowcoder.com/acm/contest/1221/E

想了一下，然后用文本编辑器魔改就过了，注意开空间要预留新加入的点。

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ls(p) ch[p][0]
#define rs(p) ch[p][1]

const int MAXN = 200000 + 5;
int ch[MAXN][2], rnd[MAXN], siz[MAXN], tot, root;
ll val[MAXN], sum[MAXN], lazy[MAXN];

int cur;

void Init() {
    root = 0, tot = 0;
}

inline void PushUp(int p) {
    siz[p] = siz[ls(p)] + siz[rs(p)] + 1;
    sum[p] = sum[ls(p)] + sum[rs(p)] + val[p];
}

inline void PushDown(int p) {
    if(lazy[p]) {
        sum[ls(p)] += 1ll * siz[ls(p)] * lazy[p];
        lazy[ls(p)] += lazy[p];
        val[ls(p)] += lazy[p];
        sum[rs(p)] += 1ll * siz[rs(p)] * lazy[p];
        lazy[rs(p)] += lazy[p];
        val[rs(p)] += lazy[p];
        lazy[p] = 0;
    }
}

void SplitRank(int p, int rk, int &x, int &y) {
    if(!p) {
        x = y = 0;
        return;
    }
    PushDown(p);
    if(rk <= siz[ls(p)]) {
        y = p;
        SplitRank(ls(p), rk, x, ls(p));
        PushUp(y);
    } else {
        x = p;
        SplitRank(rs(p), rk - siz[ls(p)] - 1, rs(p), y);
        PushUp(x);
    }
}

int Merge(int x, int y) {
    if(!x || !y)
        return x | y;
    if(rnd[x] < rnd[y]) {
        PushDown(x);
        rs(x) = Merge(rs(x), y);
        PushUp(x);
        return x;
    } else {
        PushDown(y);
        ls(y) = Merge(x, ls(y));
        PushUp(y);
        return y;
    }
}

int NewNode(ll v) {
    int p = ++tot;
    ch[p][0] = ch[p][1] = 0;
    val[p] = v, rnd[p] = rand();
    siz[p] = 1;
    sum[p] = v;
    lazy[p] = 0;
    return p;
}


//O(n)建树，返回新树的根
int st[MAXN], stop;
inline int Build(int n) {
    Init();
    stop = 0;
    for(int i = 0; i < n; ++i) {
        ll val;
        scanf("%lld", &val);
        int tmp = NewNode(val), last = 0;
        while(stop && rnd[st[stop]] > rnd[tmp]) {
            last = st[stop];
            PushUp(last);
            st[stop--] = 0;
        }
        if(stop)
            rs(st[stop]) = tmp;
        ls(tmp) = last;
        st[++stop] = tmp;
    }
    while(stop)
        PushUp(st[stop--]);
    return st[1];
}


int main() {
#ifdef Yinku
    freopen("Yinku.in", "r", stdin);
#endif // Yinku
    int n;
    scanf("%d", &n);
    root = Build(n);
    int m;
    scanf("%d", &m);
    for(int i = 1; i <= m; ++i) {
        int op;
        scanf("%d", &op);
        if(op == 1) {
            int pos;
            scanf("%d", &pos);
            int x, y;
            SplitRank(root, pos - 1, x, y);
            root = Merge(Merge(x, NewNode(0)), y);
        } else if(op == 2) {
            int l, r;
            ll v;
            scanf("%d%d%lld", &l, &r, &v);
            int x, y, z;
            SplitRank(root, l - 1, x, y);
            SplitRank(y, r + 1 - l, y, z);
            sum[y] += 1ll * siz[y] * v;
            lazy[y] += v;
            val[y] += v;
            root = Merge(Merge(x, y), z);
        } else {
            int l, r;
            scanf("%d%d", &l, &r);
            int x, y, z;
            SplitRank(root, l - 1, x, y);
            SplitRank(y, r + 1 - l, y, z);
            printf("%lld\n", sum[y]);
            root = Merge(Merge(x, y), z);
        }
    }
    return 0;
}