rt，这份代码。

#include <bits/stdc++.h>
#define For(i,a,b) for(register int i=a;i<=b;++i)
#define Rep(i,a,b) for(register int i=a;i>=b;--i)
#define ll long long
using namespace std;
inline int read() {
    char c = getchar();
    int x = 0;
    bool f = 0;

    for (; !isdigit(c); c = getchar())
        f ^= !(c ^ 45);

    for (; isdigit(c); c = getchar())
        x = x * 10 + (c ^ 48);

    if (f)
        x = -x;

    return x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int, int>pii;
typedef vector<int>vi;

#define maxn 500005
#define inf 0x3f3f3f3f

int n, m, res;
ll val[maxn];
bool cmp(int x, int y) {
    return val[x] > val[y] || (val[x] == val[y] && x < y);
}

namespace T {
int ch[maxn][2], fa[maxn], typ[maxn];
void rot(int x) {
    int y = fa[x], w = fa[x] && ch[fa[x]][1] == x;

    if (fa[y])
        ch[fa[y]][fa[y] && ch[fa[y]][1] == y] = x;

    if (x)
        fa[x] = fa[y];

    if (y)
        ch[y][w] = ch[x][!w];

    if (ch[x][!w])
        fa[ch[x][!w]] = y;

    if (x)
        ch[x][!w] = y;

    if (y)
        fa[y] = x;

    typ[x] = typ[y], typ[y] = 0;
}
void splay(int x) {
    while (fa[x]) {
        int y = fa[x];

        if (fa[y])
            rot((fa[y] && ch[fa[y]][1] == y) ^ (fa[y] && ch[fa[y]][1] == y) ? x : y);

        rot(x);
    }
}
void cut(int x) {
    splay(x);

    if (ch[x][1]) {
        fa[ch[x][1]] = 0, typ[ch[x][1]] = typ[x];
        ch[x][1] = 0;
    }
}
void link(int f, int x) {
    bool w = x > f;
    splay(x), cut(f);

    if (!ch[f][0] && !ch[f][1])
        typ[f] = w;

    if (typ[f] == w && (typ[x] == w || (!ch[x][0] && !ch[x][1])))
        ch[f][1] = x, fa[x] = f;
}
int find(int x) {
    int u = ch[x][0], res = -1;

    while (1) {
        if (cmp(x, u)) {
            res = u;

            if (!ch[u][0])
                return splay(u), res;

            u = ch[u][0];
        } else {
            if (!ch[u][1])
                return splay(u), res;

            u = ch[u][1];
        }
    }
}
}

int ch[maxn][2], fa[maxn], f[maxn][5], rt;
void up(int p) {
    if (!p)
        return;

    res -= f[p][4];
    int l = ch[p][0], r = ch[p][1], t;
    bool ok = 1;
    t = f[l][1] + f[r][1];

    if (t != f[p][2])
        f[p][2] = t, ok = 0;

    t = f[l][2] + f[r][2] + f[l][1] * f[r][1];

    if (t != f[p][3])
        f[p][3] = t, ok = 0;

    t = f[l][3] + f[l][2] * f[r][1] + f[l][1] * f[r][2] + f[r][3];
    f[p][4] = t, res += t;

    if (!ok)
        up(fa[p]);
}
void link(int f, int x) {
    if (!x)
        return;

    bool w = x > f;
    ch[f][w] = x, fa[x] = f, up(f);
    T::link(f, x);
}
void cut(int f, int x) {
    if (!x)
        return;

    bool w = x > f;
    ch[f][w] = fa[x] = 0, up(f);
    T::cut(f);
}

int son[2];
void mdf(int x, int v) {
    val[x] += v;
    son[0] = ch[x][0], son[1] = ch[x][1];
    cut(x, son[0]), cut(x, son[1]);

    while (fa[x] && cmp(x, fa[x])) {
        T::splay(x);
        int y = fa[x], w = x > y, o, z;

        // z:上旋到的点
        if (T::ch[x][0])
            z = T::find(x);
        else
            z = y;

        cut(y, x), link(y, son[!w]), son[!w] = z;

        if (fa[z])
            cut(o = fa[z], z), link(o, x);
    }

    link(x, son[0]), link(x, son[1]);

    if (!fa[x])
        rt = x;
}

signed main() {
    n = read();
    For(i, 1, n)f[i][1] = 1;
    rt = 1;
    For(i, 1, n - 1)link(i, i + 1);
    For(i, 1, n)mdf(i, read());
    m = read();
    For(_, 1, m) {
        int x = read(), y = read();
        mdf(x, y), printf("%lld\n", res - f[rt][4]);
    }
}

跑了两个记录，今天的和之前的真的差这么多？？？