Gym

 Gym - 100338E

题意：给你n，k问在1-n中能整出k的字典序最小的数。范围10¹⁸

思路：比较简单的贪心了，枚举10的幂m，然后加上k-m%k, 更新答案就可以了，数据一定要用unsigned long long，我就在这里挂了几次，查了半天。

#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>
#define LL unsigned long long
#define eps 1e-8
#define INF 0x3f3f3f3f
#define MAXN 10005
using namespace std;
LL n, k;
LL m[25];
//char s[25], res[25];
vector<char> s, t, res;
int main()
{
#ifdef ONLINE_JUDGE
    freopen("numbers.in", "r", stdin);
    freopen("numbers.out", "w", stdout);
#endif //ONLINE_JUDGE
    m[0] = 1;
    for (int i = 1; i <= 19; i++){
        m[i] = m[i - 1] * 10ULL;
    }
    while (~scanf("%I64d%I64d", &n, &k)){
        if (n == 0 && k == 0) break;
        for (int i = 0; i <= 19; i++){
            LL p = m[i] % k == 0 ? m[i] : m[i] + k - (m[i] % k);
            if (p > n) break;
            if (p % k != 0) continue;
            t.clear();
            while (p != 0){
                t.push_back(p % 10ULL + '0');
                p /= 10ULL;
            }
            s.clear();
            for (int j = t.size() - 1; j >= 0; j--){
                s.push_back(t[j]);
            }
            if (i == 0){
                res = s;
                continue;
            }
            bool flag = true;
            for (int j = 0; j < s.size(); j++){
                if (res.size() < j + 1){
                    flag = true;
                    break;
                }
                if (s[j] > res[j]){
                    flag = true;
                    break;
                }
                if (s[j] == res[j]) continue;
                flag = false;
                break;
            }
            if (flag) continue;
            res = s;
        }
        for (int i = 0; i < res.size(); i++){
            printf("%c", res[i]);
        }
        printf("
");
    }
}