题目

代码

#include <bits/stdc++.h>
using namespace std;
int cnt[10];
bool consume(int x)
{
    int need[10] = {0};
    while (x)
    {
        int k = x % 10;
        need[k]++;
        x /= 10;
    }

    for (int i = 0; i < 10; i++)
    {
        if (cnt[i] < need[i])
            return false;
    }

    for (int i = 0; i < 10; i++)
    {
        cnt[i] -= need[i];
    }

    return true;
}
int main()
{
    int i;
    for (i = 0; i < 10; i++)
        cnt[i] = 2021;
    for (i = 1; i <= 1e9; i++)
    {
        if (!consume(i))
            break;
    }

    cout << --i;
}