CF864D Make a Permutation!

思路：

贪心，构造，模拟。

实现：

 #include <bits/stdc++.h>
 using namespace std;
 int t[], a[], vis[], n;
 int main()
 {
     while (cin >> n)
     {
         memset(t, , sizeof t); memset(vis, , sizeof vis);
         int cnt = ;
         for (int i = ; i < n; i++)
         {
             cin >> a[i]; t[a[i]]++;
             if (t[a[i]] > ) cnt++;
         }
         cout << cnt << endl;
         queue<int> q;
         for (int i = ; i <= n; i++) if (!t[i]) q.push(i);
         for (int i = ; i < n; i++)
         {
             if (!t[a[i]]) continue;
             else if (t[a[i]] ==  && !vis[a[i]])
             {
                 cout << a[i] << " "; t[a[i]]--;
             }
             else
             {
                 if (vis[a[i]])
                 {
                     cout << q.front() << " "; q.pop();
                 }
                 else if (q.front() < a[i])
                 {
                     cout << q.front() << " "; q.pop();
                 }
                 else
                 {
                     cout << a[i] << " "; vis[a[i]] = ;
                 }
                 t[a[i]]--;
             }
         }
         cout << endl;
     }
     return ;
 }