題解

給n個數字 兩種操作一種將某個點修改為某個值 另一種詢問一個區間的所有元素乘積

線段樹模板提 單點修改區間查詢

AC程式碼

#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int MAXN = 5e4 + 10;
ll a[MAXN];

struct node 
{
	int l, r;
	ll v;
}tre[MAXN * 4
 
];

inline void PushUp(int x)
{
	tre[x].v = tre[x << 1].v * tre[x << 1 | 1].v % MOD;
}
void Build(int x, int l, int r)
{
	tre[x].l = l, tre[x].r = r, tre[x].v = 0;
	if (l == r)
		tre[x].v = a[l];
	else
	{
		int m = l + r >> 1;
		Build(x << 1, l, m);
		Build(x << 1 | 1, m +
 
 1, r);
		PushUp(x);
	}
}
void Update(int x, int p, ll v)
{
	int l = tre[x].l, r = tre[x].r;
	if (l == r)
		tre[x].v = v;
	else
	{
		int m = l + r >> 1;
		if (m >= p)
			Update(x << 1, p, v);
		else
			Update(x << 1 | 1, p, v);
		PushUp(x);
	}
}
ll Query(int x, int pl, int pr)
{
 

	int l = tre[x].l, r = tre[x].r;
	if (pl <= l && r <= pr)
		return tre[x].v;
	else
	{
		int m = l + r >> 1;
		ll v = 1;
		if (m >= pl)
			v = v * Query(x << 1, pl, pr) % MOD;
		if (m < pr)
			v = v * Query(x << 1 | 1, pl, pr) % MOD;
		return v;
	}
}
int main()
{
#ifdef LOCAL
	freopen("C:/input.txt", "r", stdin);
#endif
	int T;
	cin >> T;
	while (T--)
	{
		int n, q;
		cin >> n;
		for (int i = 1; i <= n; i++)
			scanf("%d", &a[i]);
		Build(1, 1, n);
		cin >> q;
		for (int i = 0; i < q; i++)
		{
			int op, x, y;
			scanf("%d%d%d", &op, &x, &y);
			if (op)
				Update(1, x, y);
			else
				printf("%lld\n", Query(1, x, y));
		}
	}

	return 0;
}