以前觉得特别难不敢看跳过的题目现在居然自己一发AC

#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 15;

int len;
int nums[N], f[N][N];

int dfs(int pos, int cnt, int k, int lead, int limit) {
    if (!pos) return cnt;
    if (!limit && !lead && ~f[pos][cnt]) return f[pos][cnt]; // 若知道从当前状态往下层搜索有多少的方案，记忆化
    int up = limit ? nums[pos] : 9, res = 0;
    for (int i = 0; i <= up; i ++ ) {
        if (!k) 
            res += dfs(pos - 1, cnt + (!lead && !i), k, lead && !i, limit && i == up);
        else 
            res += dfs(pos - 1, cnt + (i == k), k, lead && !i, limit && i == up);
    }
    return limit ? res : (lead ? res : f[pos][cnt] = res);
}

int calc(int x, int k) {
    len = 0;
    memset(f, -1, sizeof f);
    while (x) nums[ ++ len] = x % 10, x /= 10;
    return dfs(len, 0, k, 1, 1);
}

int main() {
    int l, r;
    while (cin >> l >> r, l || r) {
        if (l > r) swap(l, r);
        for (int i = 0; i <= 9; i ++ ) 
            cout << calc(r, i) - calc(l - 1, i) << ' ';
        cout << endl;
    }
    return 0;
}