作者:
炽热的
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2023-03-16 15:40:09
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所有人可见
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阅读 38
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long i64;
int len;
int nums[20];
i64 f[20][20][2000];
i64 dfs(int pos, int mid, int sum, int lead, int limit) {
if (!pos) return !lead && !sum;
if (!limit && !lead && ~f[pos][mid][sum]) return f[pos][mid][sum];
int up = limit ? nums[pos] : 9;
i64 res = 0;
for (int i = 0; i <= up; i ++ )
res += dfs(pos - 1, mid, sum + i * (pos - mid), lead && !i, limit && i == up);
return limit ? res : (lead ? res : f[pos][mid][sum] = res);
}
i64 calc(i64 x) {
len = 0;
while (x) nums[ ++ len] = x % 10, x /= 10;
i64 res = 0;
for (int i = 1; i <= len; i ++ ) res += dfs(len, i, 0, 1, 1);
return res;
}
void solve() {
i64 l, r;
memset(f, -1, sizeof f);
scanf("%lld%lld", &l, &r);
if (l == 0) printf("%lld\n", calc(r) + 1);
else printf("%lld\n", calc(r) - calc(l - 1));
}
int main() {
int _; scanf("%d", &_);
while (_ -- ) solve();
return 0;
}