求问怎么缩短代码长度 我的代码实在是太长了，别人写 80 行的题我可能要写 100+。这是我的几份代码，有没有大佬能指点一下：

树套树

#include <bits/stdc++.h>
#define MAXN 500000
#define INF 2147483647
#define lc(p) p<<1
#define rc(p) p<<1|1
#define endl "\n"

using namespace std;

void read(int &x) {
	x = 0; char c;
	while ((c = getchar()) < '0' || c > '9');
	while ('0' <= c && c <= '9')
		x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
}

mt19937 rnd((int)('T' + 'Q') * time(0));

int idx, dl, dr, tmp;
int a[MAXN+5];

struct node {
	int lc, rc;
	int key, val, siz;
	node() { key = val = siz = lc = rc = 0; }	
} t[(MAXN<<3)+5];

struct fhq_treap {
	int rt;
	fhq_treap() { rt = 0; }
	inline int newnode(int x) {
		t[++idx].key = rnd();
		t[idx].siz = 1, t[idx].val = x;
		return idx; 
	}
	inline void pushup(int p) { t[p].siz = t[t[p].lc].siz + 1 + t[t[p].rc].siz; }
	inline void split(int p, int x, int &l, int &r) {
		if (!p) {
			l = r = 0;
			return;
		}
		if (t[p].val <= x) {
			l = p;
			split(t[p].rc, x, t[p].rc, r);
		} else {
			r = p;
			split(t[p].lc, x, l, t[p].lc);
		}
		pushup(p);
	}
	inline int merge(int l, int r) {
		if (!l || !r) return l | r;
		if (t[l].key <= t[r].key) {
			t[l].rc = merge(t[l].rc, r);
			pushup(l);
			return l;
		} else {
			t[r].lc = merge(l, t[r].lc);
			pushup(r);
			return r;
		}
	}
	inline void insert(int x) {
		split(rt, x, dl, dr);
		rt = merge(merge(dl, newnode(x)), dr);
	}
	inline void erase(int x) {
		split(rt, x - 1, dl, dr);
		split(dr, x, tmp, dr);
		tmp = merge(t[tmp].lc, t[tmp].rc);
		rt = merge(merge(dl, tmp), dr);
	}
	inline int lower(int x) {
		split(rt, x - 1, dl, dr);
		tmp = t[dl].siz;
		rt = merge(dl, dr);
		return tmp;
	}
	inline int upper(int x) {
		split(rt, x, dl, dr);
		tmp = t[dr].siz;
		rt = merge(dl, dr);
		return tmp;
	}
	inline int count(int x) { 
		split(rt, x - 1, dl, dr);
		split(dr, x, tmp, dr);
		x = t[tmp].siz;
		rt = merge(merge(dl, tmp), dr);
		return x;
	}
	inline int rank(int x) { return lower(x) + 1; }
	inline int premax(int x) {
		split(rt, x - 1, dl, dr);
		if (!dl) {
			rt = merge(dl, dr);
			return -INF;
		}
		x = dl;
		while (t[x].rc) x = t[x].rc;
		rt = merge(dl, dr);
		return t[x].val;
	}
	inline int sufmin(int x) {
		split(rt, x, dl, dr);
		if (!dr) {
			rt = merge(dl, dr);
			return INF;
		}
		x = dr;
		while (t[x].lc) x = t[x].lc;
		rt = merge(dl, dr);
		return t[x].val;
	}
};

struct Node {
	int l, r;
	fhq_treap f;
} seg[(MAXN<<2)+5];

inline void build(int p, int l, int r) {
	for (int i = l; i <= r; ++i)
		seg[p].f.insert(a[i]);
	seg[p].l = l, seg[p].r = r;
	if (l == r) return;
	int mid = (l + r) >> 1;
	build(lc(p), l, mid), build(rc(p), mid + 1, r);
}

inline void change(int p, int x, int y) {
	seg[p].f.erase(a[x]), seg[p].f.insert(y);
	if (seg[p].l == seg[p].r) {
		a[x] = y;
		return;
	}
	int mid = (seg[p].l + seg[p].r) >> 1;
	if (x <= mid) change(lc(p), x, y);
	else change(rc(p), x, y); 
}

inline int lower(int l, int r, int x, int p = 1) {
	if (seg[p].l > r || seg[p].r < l) return 0;
	if (l <= seg[p].l && seg[p].r <= r) return seg[p].f.lower(x);
	return lower(l, r, x, lc(p)) + lower(l, r, x, rc(p)); 
}

inline int Rank(const int &l, const int & r, const int & x) { return lower(l, r, x) + 1; } 

inline int premax(int l, int r, int x, int p = 1) {
	if (seg[p].l > r || seg[p].r < l) return -INF;
	if (l <= seg[p].l && seg[p].r <= r) return seg[p].f.premax(x);
	return max(premax(l, r, x, lc(p)), premax(l, r, x, rc(p)));
}

inline int sufmin(int l, int r, int x, int p = 1) {
	if (seg[p].l > r || seg[p].r < l) return INF;
	if (l <= seg[p].l && seg[p].r <= r) return seg[p].f.sufmin(x);
	return min(sufmin(l, r, x, lc(p)), sufmin(l, r, x, rc(p)));
}

signed main() {
	int n, m; read(n), read(m);
	for (int i = 1; i <= n; ++i) read(a[i]);
	build(1, 1, n);
	while (m--) {
		int opt, l, r, x, y;
		read(opt);
		if (opt == 1) {
			read(l), read(r), read(x);
			printf("%d\n", Rank(l, r, x));
		} else if (opt == 2) {
			read(l), read(r), read(x);
			int L = 0, R = 1e8, ans;
			while (L <= R) {
				int mid = (L + R) >> 1;
				if (Rank(l, r, mid) <= x) L = mid + 1, ans = mid;
				else R = mid - 1; 
			}
			printf("%d\n", ans);
		} else if (opt == 3) {
			read(x), read(y);
			change(1, x, y);
		} else if (opt == 4) {
			read(l), read(r), read(x);
			printf("%d\n", premax(l, r, x));
		} else {
			read(l), read(r), read(x);
			printf("%d\n", sufmin(l, r, x));
		}
	}
	return 0;
} 

点分治

#include <bits/stdc++.h>
using namespace std;

#define endl '\n'

const int N = 2e5;

int n, rt, ans, siz[N+5], d[N+5], fr[N+5], cnt[N+5];
bool vis[N+5];

struct edge {int v,w;};vector<edge> G[N+5];
vector<int> num, v[N+5];	

void groot(int x, int fa, int sum) {
	int mx = 0;
	siz[x] = 1;
	for (edge p : G[x]) {
		int y = p.v, c = p.w;
		if (y == fa || vis[y]) continue;
		groot(y, x, sum);
		siz[x] += siz[y];
		mx = max(mx, siz[y]);
	}
	mx = max(mx, sum - siz[x]);
	if (mx <= (sum + 1) / 2) rt = x;
}

void gdis(int x, int fa) {
	v[fr[x]].push_back(x);
	num.push_back(x);
	for (edge p : G[x]) {
		int y = p.v, c = p.w;
		if (y == fa || vis[y]) continue;
		d[y] = (d[x] + c) % 3;
		if (!fa) fr[y] = y;
		else fr[y] = fr[x];
		gdis(y, x);
	}
}

void calc(int x) {
	fr[x] = x, d[x] = 0;
	num.clear();
	gdis(x, 0);
	for (int x : num) ++cnt[d[x]];
	for (int x : num) {
		for (int y : v[fr[x]]) --cnt[d[y]];
		for (int y : v[fr[x]]) ans += cnt[(3 - d[y]) % 3];
		for (int y : v[fr[x]]) ++cnt[d[y]];
		v[fr[x]].clear();
	}
	for (int x : num) cnt[d[x]] = 0;
}

void dfs(int x) {
	calc(x);
	vis[x] = 1;
	for (edge p : G[x]) {
		int y = p.v;
		if (!vis[y]) {
			groot(y, x, 0); groot(y, x, siz[y]);
			dfs(rt);
		}
	}
}

signed main() {
//	ios::sync_with_stdio(false);
//	cin.tie(nullptr), cout.tie(nullptr);
	cin >> n;
	for (int i = 1; i < n; ++i) {
		int u, v, w;
		cin >> u >> v >> w;
		G[u].push_back({v, w}), G[v].push_back({u, w});
	}
	dfs(1);
	int x = ans + n, y = n * n;
	int g = __gcd(x, y);
	x /= g, y /= g;
	cout << x << "/" << y << endl;
	return 0;
}

线段树：

#include <bits/stdc++.h>
#define MAXN 200000
#define INF 2147483647
#define lc(p) p<<1
#define rc(p) p<<1|1
#define endl "\n"

using namespace std;

void read(int &x) {
	x = 0; char c; bool f = 1;
	while ((c = getchar()) < '0' || c > '9') 
		if (c == '-') f ^= 1;
	while ('0' <= c && c <= '9')
		x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
	x = f ? x : -x; 
}

mt19937 rnd(1000);

int idx, dl, dr, tmp;
int a[MAXN+5];

struct node {
	int l, r;
	int mx[2], cnt[2];
	node() {
		mx[0] = mx[1] = -INF;
		cnt[0] = cnt[1] = 0;
		l = r = 0;
	}
} seg[(MAXN<<2)+5], emp;

node merge(node a, node b) {
	node c; c.l = a.l, c.r = b.r;
	if (a.mx[0] > b.mx[0]) {
		c.mx[0] = a.mx[0], c.cnt[0] = a.cnt[0];
		if (a.mx[1] > b.mx[0]) c.mx[1] = a.mx[1], c.cnt[1] = a.cnt[1];
		else if (a.mx[1] < b.mx[0]) c.mx[1] = b.mx[0], c.cnt[1] = b.cnt[0];
		else c.mx[1] = a.mx[1], c.cnt[1] = a.cnt[1] + b.cnt[0];
	} else if (a.mx[0] < b.mx[0]) {
		c.mx[0] = b.mx[0], c.cnt[0] = b.cnt[0];
		if (b.mx[1] > a.mx[0]) c.mx[1] = b.mx[1], c.cnt[1] = b.cnt[1];
		else if (b.mx[1] < a.mx[0]) c.mx[1] = a.mx[0], c.cnt[1] = a.cnt[0];
		else c.mx[1] = b.mx[1], c.cnt[1] = b.cnt[1] + a.cnt[0];
	} else {
		c.mx[0] = b.mx[0], c.cnt[0] = a.cnt[0] + b.cnt[0];
		if (b.mx[1] > a.mx[1]) c.mx[1] = b.mx[1], c.cnt[1] = b.cnt[1];
		else if (b.mx[1] < a.mx[1]) c.mx[1] = a.mx[1], c.cnt[1] = a.cnt[1];
		else c.mx[1] = b.mx[1], c.cnt[1] = b.cnt[1] + a.cnt[1];
	}
	return c;
}

void build(int p, int l, int r) {
	seg[p].l = l, seg[p].r = r;
	if (l == r) {
		seg[p].cnt[0] = 1, seg[p].mx[0] = a[l];
		seg[p].cnt[1] = 0, seg[p].mx[1] = 0;
		return;
	}
	int mid = (l + r) >> 1;
	build(lc(p), l, mid), build(rc(p), mid + 1, r);
	seg[p] = merge(seg[lc(p)], seg[rc(p)]);
//	cout<<l<<' '<<r<<":\n";
//	cout<<seg[p].cnt[0]<<' '<<seg[p].cnt[1]<<endl; 
}

void change(int p, int x, int y) {
	if (seg[p].l == seg[p].r) {
		seg[p].cnt[0] = 1, seg[p].mx[0] = y;
		seg[p].cnt[1] = 0, seg[p].mx[1] = 0;
		return;
	}
	int mid = (seg[p].l + seg[p].r) >> 1;
	if (x <= mid) change(lc(p), x, y);
	else change(rc(p), x, y); 
	seg[p] = merge(seg[lc(p)], seg[rc(p)]);
}

node query(int p, int l, int r) {
	if (seg[p].l > r || seg[p].r < l) return emp;
	if (l <= seg[p].l && seg[p].r <= r) {
//		cout<<seg[p].l<<' '<<seg[p].r<<endl;
		return seg[p];
	}
	return merge(query(lc(p), l, r), query(rc(p), l, r));
}

signed main() {
	int n, m; read(n), read(m);
	for (int i = 1; i <= n; ++i) read(a[i]);
	build(1, 1, n);
	while (m--) {
		int opt, l, r, x, y;
		read(opt);
		if (opt == 1) {
			read(x), read(y);
			change(1, x, y);
		} else {
			read(l), read(r);
			node ans = query(1, l, r);
			printf("%d\n", ans.cnt[1]);
		} 
	}
	return 0;
}