[HDU3709]Balanced Number

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
using namespace std;
#define LL long long

LL read() {
	LL x = 0, f = 1; char c = getchar();
	while(!isdigit(c)){ if(c == ‘-‘) f = -1; c = getchar(); }
	while(isdigit(c)){ x = x * 10 + c - ‘0‘; c = getchar(); }
	return x * f;
}

#define maxn 20
#define maxs 1800
LL f[maxn][maxn][10][maxs];

int num[maxn];
LL sum(LL x) {
	if(!x) return 1;
	int cnt = 0; LL tx = x;
	while(x) num[++cnt] = x % 10, x /= 10;
	LL ans = 0;
	for(int i = cnt - 1; i; i--)
		for(int k = 1; k <= i; k++)
			for(int j = 1; j <= 9; j++) ans += f[k][i][j][0];
	for(int i = cnt; i; i--) {
		for(int k = cnt; k; k--) {
			int s = 0;
			for(int x = cnt; x > i; x--) s += (x - k) * num[x];
			if(s < 0 || s >= maxs) continue;
			for(int j = i < cnt ? 0 : 1; j < num[i]; j++) {
				ans += f[k][i][j][s];
//				if(!j && !s && i > 1) ans--;
			}
		}
	}
	for(int k = 1; k <= cnt; k++) {
		int s = 0;
		for(int x = 1; x <= cnt; x++) s += (x - k) * num[x];
		if(!s){ ans++; break; }
	}
	ans++;
	return ans;
}

int main() {
	for(int j = 0; j <= 9; j++) f[1][1][j][0] = 1;
	for(int k = 2; k < maxn; k++)
		for(int j = 0; j <= 9; j++) f[k][1][j][(k-1)*j] = 1;
	for(int k = 1; k < maxn; k++)
		for(int i = 1; i < maxn - 1; i++)
			for(int j = 0; j <= 9; j++)
				for(int s = 0; s < maxs; s++) if(f[k][i][j][s]) {
					for(int x = 0; x <= 9 && s + (k - i - 1) * x >= 0; x++)
						if(s + (k - i - 1) * x < maxs) f[k][i+1][x][s+(k-i-1)*x] += f[k][i][j][s];
//					printf("%d %d %d %d: %lld\n", k, i, j, s, f[k][i][j][s]);
				}
	int T = read();
	while(T--) {
		LL l = read(), r = read();
		LL ans = sum(r); if(l) ans -= sum(l - 1);
		printf("%lld\n", ans);
	}
	
	return 0;
}