HihoCoder - 1077（线段树单点修改+区间查询，模板）

代码：

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

class SegmentTree 
{
public:
	struct node {
		int val;
		node() { val = 0; }
		node(int val) { this->val = val; }
	};
	SegmentTree();
	SegmentTree(const vector<node>& v);
	void updata(int pos, const node& val);
	node query(int l, int r);
	void clear();
private:
	vector<node>tr;
	int n;

	inline node merge(const node& l, const node& r);
	void build(const vector<node>& a, int nl, int nr, int now);
	node query(int l, int r, int nl, int nr, int now);
	void updata(int pos, const node& val, int nl, int nr, int now);
};

inline SegmentTree::node SegmentTree::merge(const node& l, const node& r) { // 元素合并函数
	return node(min(l.val, r.val));
}
void SegmentTree::build(const vector<node>& a, int nl, int nr, int now) {
	if (nl == nr) {
		while (tr.size() <= now) {
			tr.push_back(node());
		}
		tr[now] = a[nl-1];
		return;
	}
	int mid = (nl + nr) / 2;
	build(a, nl, mid, now << 1);
	build(a, mid + 1, nr, now << 1 | 1);
	tr[now] = merge(tr[now << 1], tr[now << 1 | 1]);
}
SegmentTree::node SegmentTree::query(int l, int r, int nl, int nr, int now) {
	node ret;
	if (l <= nl && nr <= r) {
		return tr[now];
	}
	int mid = (nl + nr) / 2;
	bool flag = false;
	if (mid >= l) {
		flag = true;
		ret = query(l, r, nl, mid, now << 1);
	}
	if (mid + 1 <= r) {
		if (flag == true) {
			ret = merge(ret, query(l, r, mid + 1, nr, now << 1 | 1));
		}
		else {
			ret = query(l, r, mid + 1, nr, now << 1 | 1);
		}
	}
	return ret;
}
void SegmentTree::updata(int pos, const node& val, int nl, int nr, int now) {
	if (nl == nr) {
		tr[now] = val;
		return;
	}
	int mid = (nl + nr) / 2;
	if (pos <= mid) {
		updata(pos, val, nl, mid, now << 1);
	}
	else {
		updata(pos, val, mid + 1, nr, now << 1 | 1);
	}
	tr[now] = merge(tr[now << 1], tr[now << 1 | 1]);
}
SegmentTree::SegmentTree() {
	tr.clear();
	n = 0;
}
SegmentTree::SegmentTree(const vector<node>& v){
	n = v.size();
	build(v, 1, v.size(), 1);
}
void SegmentTree::updata(int pos, const node& val) {
	updata(pos, val, 1, n, 1);
}
SegmentTree::node SegmentTree::query(int l, int r) {
	return query(l, r, 1, n, 1);
}
void SegmentTree::clear() {
	tr.clear();
	n = 0;
}

int main()
{
	ios::sync_with_stdio(false);
	int n, m;
	SegmentTree ans;
	vector<SegmentTree::node>a;
	cin >> n;
	for (int i = 0; i < n; i++) {
		int temp;
		cin >> temp;
		a.push_back(SegmentTree::node(temp));
	}
	ans = SegmentTree(a);
	cin >> m;
	for (int i = 0; i < m; i++) {
		int op;
		cin >> op;
		if (op == 0) {
			int l, r;
			cin >> l >> r;
			cout << ans.query(l, r).val << endl;
		}
		else {
			int pos, val;
			cin >> pos >> val;
			ans.updata(pos, val);
		}
	}
}