CF1023D Array Restoration

思路：

使用set即可，细节很多，容易出错。

实现：

 #include <bits/stdc++.h>
 using namespace std;
 const int INF = 0x3f3f3f3f;
 const int MAXN = ;
 int a[MAXN], l[MAXN], r[MAXN];
 int main()
 {
     int n, q;
     while (cin >> n >> q)
     {
         for (int i = ; i <= q; i++) { l[i] = INF; r[i] = -INF; }
         int c0 = , cq = ;
         for (int i = ; i <= n; i++)
         {
             cin >> a[i];
             c0 += a[i] == ;
             cq += a[i] == q;
             if (a[i] == ) continue;
             l[a[i]] = min(l[a[i]], i);
             r[a[i]] = max(r[a[i]], i);
         }
         if (!c0 && !cq) { cout << "NO" << endl; continue; }
         set<int> st;
         bool flg = true;
         for (int i = ; i <= n; i++)
         {
             if (i == l[a[i]]) st.insert(a[i]);
             if (a[i] && !st.empty() && *st.rbegin() != a[i]) { flg = false; break; }
             int tmp = -;
             if (a[i] == )
             {
                 if (cq == ) { tmp = q; cq++; }
                 else if (!st.empty()) tmp = *st.rbegin();
                 else tmp = ;
             }
             if (i == r[a[i]]) st.erase(st.find(a[i]));
             if (tmp != -) a[i] = tmp;
         }
         if (!cq || !flg) { cout << "NO" << endl; continue; }
         cout << "YES" << endl;
         for (int i = ; i <= n; i++) cout << a[i] << " ";
         cout << endl;
     }
     return ;
 }