AC代码

#include <cstdio>
#include <cstring>

namespace read
{
unsigned int lst = 7, seed, m;

typedef unsigned int ui ;
ui randNum( ui& seed , ui last , const ui m){ 
    seed = seed * 17 + last ; return seed % m + 1; 
}

int read()
{
	return randNum(seed, lst, m);
}
}

const int MX = 100010, MXM = 1000010, MXT = MXM * 5;

template <typename T>
struct balTree
{
#define get(x) (son[fa[x]][1] == x)
#define update(x) (siz[x] = siz[son[x][0]] + siz[son[x][1]] + cnt[x])
private:
	T val[MXT];
	int fa[MXT], son[MXT][2], cnt[MXT], siz[MXT], tot, rt;
	
	void rotate(int x)
	{
		if (rt == fa[x])
		{
			rt = x;
		}
		int ffa = fa[fa[x]], dr = get(x);
		son[ffa][get(fa[x])] = x;
		fa[son[x][not dr]] = fa[x];
		son[fa[x]][dr] = son[x][not dr];
		son[x][not dr] = fa[x];
		fa[fa[x]] = x;
		fa[x] = ffa;
		update(son[x][not dr]);
		update(x);
	}
	
	void splay(int x)
	{
		while (x != rt)
		{
			if (fa[x] != rt)
			{
				rotate(get(x) == get(fa[x]) ? fa[x] : x);
			}
			rotate(x);
		}
	}
	
	int find(T x)
	{
		int p = rt;
		while (val[p] != x)
		{
			p = son[p][val[p] < x];
		}
		return p;
	}
	
public:
	void insert(T x)
	{
		if (not rt)
		{
			fa[rt = ++tot] = 0;
		}
		else
		{
			int p = rt, pfa;
			while (p)
			{
				if (val[p] == x)
				{
					cnt[p]++;
					update(p);
					splay(p);
					return;
				}
				pfa = p;
				p = son[p][val[p] < x];
			}
			son[pfa][val[pfa] < x] = ++tot;
			fa[tot] = pfa;
		}
		val[tot] = x;
		cnt[tot] = 1;
		son[tot][0] = son[tot][1] = 0;
		update(tot);
		splay(tot);
	}
	
	void del(T x)
	{
		splay(find(x));
		if (cnt[rt] > 1)
		{
			cnt[rt]--;
			update(rt);
		}
		else if (not son[rt][0] and not son[rt][1])
		{
			rt = 0;
		}
		else if (son[rt][0] and son[rt][1])
		{
			int t = son[rt][1], p = rt = son[rt][0];
			fa[rt] = 0;
			while (son[p][1])
			{
				p = son[p][1];
			}
			splay(p);
			son[rt][1] = t;
			fa[t] = rt;
			update(p);
		}
		else
		{
			rt = son[rt][(bool)son[rt][1]];
		}
	}
	
	int rk(T x)
	{
		int p = rt, ret = 0;
		while (p)
		{
			if (val[p] <= x)
			{
				ret += siz[son[p][0]] + (val[p] < x) * cnt[p];
				p = son[p][1];
			}
			else
			{
				p = son[p][0];
			}
		}
		return ret;
	}
	
	void clear()
	{
		tot = rt = 0;
	}
#undef get
#undef update
};

struct part
{
	int ac, tim;
	
	void operator+= (int t)
	{
		ac++;
		tim += t;
	}
	
	bool operator== (part oth)
	{
		return ac == oth.ac and tim == oth.tim;
	}
	
	bool operator!= (part oth)
	{
		return not operator== (oth);
	}
	
	bool operator< (part oth)
	{
		return ac == oth.ac ? tim < oth.tim : ac > oth.ac;
	}
	
	bool operator<= (part oth)
	{
		return operator< (oth) or operator== (oth);
	}
} a[MX];

balTree <part> tr;

int main()
{
	int t, n, m, x, tim;
	scanf("%d", &t);
	while (t--)
	{
		scanf("%d%d%d", &n, &m, &read::seed);
		read::m = n;
		for (int i = 1; i <= n; i++)
		{
			a[i] = { 0, 0 };
			tr.insert(a[i]);
		}
		while (m--)
		{
			x = read::read();
			tim = read::read();
			tr.del(a[x]);
			a[x] += tim;
			tr.insert(a[x]);
			printf("%d\n", read::lst = tr.rk(a[x]));
		}
		tr.clear();
	}
}

其中insert函数当树是空的时会把根的父亲清空，但在函数del中当根只有一个儿子时却不会

如果我在insert中不清空根的父亲，前两个点就会T

为什么会这样