卡第五个点，不知道咋改了，大神帮忙调一下

#include<bits/stdc++.h>
using namespace std;
const int N=500;
typedef pair<int, int> PII;

int a[N];
bool mk[N];
string s;
stack<int> b;
int n, k;

void outputs()
{
    int flag = 0;
    queue <int> ans;
    for (int i = 0; i < n; i ++ )
    {
        if (mk[i])
        {
            if(a[i] || flag)
            {
                ans.push(a[i]);
                flag = 1;
            }
        }
    }
    if(ans.empty()) cout << 0;
    else
    {
        while (ans.size())
        {
            cout << ans.front();
            ans.pop();
        }
    }
}

void solve()
{
    cin >> s >> k;
    n = s.length();
    for (int i = 0; i < n; i ++ )
    {
        a[i] = s[i] - '0';
    }
    
    int cnt = 0;
    while (1)
    {
        for (int i = 0; i < n; i ++ )
            if (!mk[i])
            {
                while (b.size())
                {
                    int t = b.top();
                    if (a[t] > a[i])
                        b.pop();
                    else
                        break;
                }
                if (b.empty() || cnt < n - k)
                {
                    b.push(i);
                }
            }
        while (b.size() > n - k)    b.pop();
        while (b.size())
        {
            int t = b.top();
            b.pop();
            mk[t] = true;
            cnt ++;
            if(cnt == n - k)
            {
                outputs();
                return;
            }
        }
    }
    
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
//	cin >> t;
    while( t -- )
    {
        solve();
    }
}