Problem:
RMQ and RUQ

Write a program which manipulates a sequence A = {a0, a1, . . . , an−1} with the following operations:

update(s, t, x): change as, as+1, ..., at to x.

find(s, t): report the minimum element in as, as+1, ..., at.

Note that the initial values of ai (i = 0, 1, . . . , n−1) are 231-1.

Input

n q
query1
query2
:
queryq

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, ith query queryi is given in the following format:

0 s t x

or

1 s t

The first digit represents the type of the query. '0' denotes update(s, t, x) and '1' denotes find(s, t).

Output

For each find operation, print the minimum value.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

0 ≤ s ≤ t < n

0 ≤ x < 231−1

Sample Input 1

3 5
0 0 1 1
0 1 2 3
0 2 2 2
1 0 2
1 1 2

Sample Output 1

1
2

Sample Input 2

1 3
1 0 0
0 0 0 5
1 0 0

Sample Output 2

2147483647
5

Solution in C++14 (judge verdict: Accepted)

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

struct RURM {
	using t1 = int;
	using t2 = int;
	static t1 id1() { return INT_MAX; }
	static t2 id2() { return -1; }
	static t1 op1(const t1& l, const t1& r) { return min(l, r); }
	static t1 op2(const t1& l, const t2& r) { return r != -1 ? r : l; }
	static t2 op3(const t2& l, const t2& r) { return r != -1 ? r : l; }
};

template <typename M>
class LazySegmentTree {
	using T1 = typename M::t1;
	using T2 = typename M::t2;
	const int n;
	vector<T1> data;
	vector<T2> lazy;
	int size(int n) {
		int res = 1;
		while (res < n) res <<= 1;
		return res;
	}
	void push(int node) {
		if (lazy[node] == M::id2()) return;
		if (node < n) {
			lazy[node * 2] = M::op3(lazy[node * 2], lazy[node]);
			lazy[node * 2 + 1] = M::op3(lazy[node * 2 + 1], lazy[node]);
		}
		data[node] = M::op2(data[node], lazy[node]);
		lazy[node] = M::id2();
	}
	void suc(int l, int r, int node, int lb, int ub, T2 val) {
		if (ub <= l || r <= lb) return;
		if (l <= lb && ub <= r) {
			lazy[node] = M::op3(lazy[node], val);
			return;
		}
		push(node);
		int c = (lb + ub) / 2;
		suc(l, r, node * 2, lb, c, val);
		suc(l, r, node * 2 + 1, c, ub, val);
		data[node] = M::op1(M::op2(data[node * 2], lazy[node * 2]), M::op2(data[node * 2 + 1], lazy[node * 2 + 1]));
	}
	T1 sub(int l, int r, int node, int lb, int ub) {
		if (ub <= l || r <= lb) return M::id1();
		if (l <= lb && ub <= r) return M::op2(data[node], lazy[node]);
		int c = (lb + ub) / 2;
		return M::op2(M::op1(sub(l, r, node * 2, lb, c), sub(l, r, node * 2 + 1, c, ub)), lazy[node]);
	}
public:
	LazySegmentTree(int n_) : n(size(n_)), data(n * 2, M::id1()), lazy(n * 2, M::id2()) {}
	LazySegmentTree(int n_, T1 v1, T2 v2) : n(size(n_)), data(n * 2, v1), lazy(n * 2, v2) {}
	LazySegmentTree(const vector<T1>& data_)
		: n(size(data_.size())), data(n * 2, M::id1()), lazy(n * 2, M::id2()) {
		init(data_);
	}
	void init() {
		for (int i = n - 1; i >= 1; i--) data[i] = M::op1(data[i * 2], data[i * 2 + 1]);
	}
	void init(const vector<T1>& data_) {
		for (int i = 0; i < (int)data_.size(); i++) data[i + n] = data_[i];
		init();
	}
	void update(int l, int r, T2 val) {
		suc(l, r + 1, 1, 0, n, val);
	}
	T1 find(int l, int r) {
		return sub(l, r + 1, 1, 0, n);
	}
};

int main()
{
	ios::sync_with_stdio(false), cin.tie(0);
	int n, q, com, x, y, val;
	cin >> n >> q;
	LazySegmentTree<RURM> st(n);
	while (q--) {
		cin >> com >> x >> y;
		if (com) {
			printf("%d\n", st.find(x, y));
		}
		else {
			cin >> val;
			st.update(x, y, val);
		}
	}
	return 0;
}