洛谷多校 - Earthquake（线段树）

    线段树维护，三个lazy数组表示这个区间分别有个从右到左，全部，从左到右的数据覆盖。

#include<bits/stdc++.h>
using namespace std;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
const int N = 5e5 + 10;
int lazy[N * 6][3], c[N * 6];
void pushup(int rt) {
	c[rt] = max(c[rt << 1], c[rt << 1 | 1]);
}
void pushdown(int l,int r,int rt) {
	int m = (l + r) >> 1;
	if (lazy[rt][0]) {
		int t = lazy[rt][0];
		lazy[rt << 1][0] = max(lazy[rt << 1][0], t);
		lazy[rt << 1 | 1][0] = max(lazy[rt << 1 | 1][0], t - (m - l + 1));
	}
	if (lazy[rt][1]) {
		int t = lazy[rt][1];
		lazy[rt << 1][1] = max(lazy[rt << 1][1], t);
		lazy[rt << 1 | 1][1] = max(lazy[rt << 1 | 1][1], t);
	}
	if (lazy[rt][2]) {
		int t = lazy[rt][2];
		lazy[rt << 1][2] = max(lazy[rt << 1][2], t - (r - m));
		lazy[rt << 1 | 1][2] = max(lazy[rt << 1 | 1][2], t);
	}
	c[rt << 1] = max(c[rt << 1], max(lazy[rt << 1][0], 
		max(lazy[rt << 1][1], lazy[rt << 1][2])));
	c[rt << 1 | 1] = max(c[rt << 1 | 1], max(lazy[rt << 1 | 1][0],
		max(lazy[rt << 1 | 1][1], lazy[rt << 1 | 1][2])));
}
void change(int l, int r, int rt, int L, int R, int x,int type) {
	if (L <= l && r <= R) {
		lazy[rt][type] = max(lazy[rt][type], x);
		c[rt] = max(c[rt], lazy[rt][type]);
		return;
	}
	pushdown(l, r, rt);
	int m = (l + r) >> 1;
	if (type == 1) {
		if (L <= m) {
			change(lson, L, R, x, type);
		}
		if (R > m) {
			change(rson, L, R, x, type);
		}
	}
	else if (type == 0) {
		if (L <= m) {
			change(lson, L, R, x, type);
		}
		if (R > m) {
			if (L <= m) {
				change(rson, L, R, x - (m - L + 1), type);
			}
			else {
				change(rson, L, R, x, type);
			}
		}
	}
	else {
		if (L <= m) {
			if (R > m) {
				change(lson, L, R, x - (R - m), type);
			}
			else {
				change(lson, L, R, x, type);
			}
		}
		if (R > m) {
			change(rson, L, R, x, type);
		}
	}
	pushup(rt);
}
int query(int l, int r, int rt,int L,int R) {
	int ans = 0;
	if (L <= l && r <= R) {
		return c[rt];
	}
	int m = (l + r) >> 1;
	pushdown(l, r, rt);
	if (L <= m) {
		ans = max(ans, query(lson, L, R));
	}
	if (R > m) {
		ans = max(ans, query(rson, L, R));
	}
	return ans;
}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n, q;
	cin >> n >> q;
	while (q--) {
		int a, b, c, d;
		cin >> d >> a >> b;
		if (d == 1) {
			cin >> c;
			change(1, n, 1, a, b, c, 1);
			if (a != 1 && c != 1) {
				change(1, n, 1, 1, a - 1, c - 1, 2);
			}
			if (b != n && c != 1) {
				change(1, n, 1, b + 1, n, c - 1, 0);
			}
		}
		else {
			cout << query(1, n, 1, a, b) << "\n";
		}
	}
	return 0;
}
/*
1 2 3 4 5
3 5 7 9
*/