分块，#62 TLE。

代码：

#include <string>
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;

constexpr int N = 1e5 + 5, M = 330;
int a[N], len;
int f[M];

inline int get(register const int& x)
{
	return (x - 1) / len;
}

inline int lplace(register const int& x)
{
	return x * len + 1;
}

inline int rplace(register const int& x)
{
	return lplace(x + 1) - 1;
}

int p[] = { 4, 7, 44, 47, 74, 77, 444, 447, 474, 477, 744, 747, 774, 777, 4444, 4447, 4474, 4477, 4744, 4747, 4774, 4777, 7444, 7447, 7474, 7477, 7744, 7747, 7774, 7777 };
bool flag[N];

int main()
{
	register int n, m;
	scanf("%d%d", &n, &m);
	len = sqrt(n);
	for (register int i(0); i < 30; i = -~i) flag[p[i]] = true;
	for (register int i(1); i <= n; i = -~i) scanf("%d", &a[i]);
	for (register int i(1); i <= n; i = -~i)
	{
		flag[a[i]] ? ++f[get(i)] : 1;
	}
	while (m--)
	{
		string ch;
		cin >> ch;
		if (ch[0] == 'a')
		{
			register int l, r, d;
			scanf("%d%d%d", &l, &r, &d);
			for (register int i(l); i <= r; i = -~i)
			{
				register int place(get(i));
				f[place] -= flag[a[i]];
				a[i] += d;
				f[place] += flag[a[i]];
			}
		}
		else
		{
			register int sum = 0, l, r;
			scanf("%d%d", &l, &r);
			register int ls(get(l)), rs(get(r));
			if (ls == rs)
			{
				for (register int i(l); i <= r; i = -~i) sum += flag[a[i]];
			}
			else
			{
				register int lp = lplace(ls + 1), rp = rplace(rs - 1);
				for (register int i(l); i < lp; i = -~i) sum += flag[a[i]];
				for (register int i(rp + 1); i <= r; i = -~i) sum += flag[a[i]];
				register int nl(get(lp)), nr(get(rp));
				for (register int i(nl); i <= nr; i++)
				{
					sum += f[i];
				}
			}
			printf("%d\n", sum);
		}
	}
	return 0;
}