new file: P12903.cpp

P12903.cpp

@@ -0,0 +1,75 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define int long long
+int n, m;
+int a[100005];
+long double f[2][10];
+int op;
+bitset<100005> b[2][10];
+signed main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++)
+    {
+        cin >> a[i];
+    }
+    for (int i = 1; i <= n; i++)
+    {
+        for (int j = 0; j < 10; j++)
+        {
+            f[op][j] = f[op ^ 1][j];
+            b[op][j] = b[op ^ 1][j];
+        }
+        if (f[op][a[i] % 10] < a[i])
+        {
+            f[op][a[i] % 10] = log(a[i]);
+            b[op][a[i] % 10].reset();
+            b[op][a[i] % 10].set(i);
+        }
+        for (int j = 0; j < 10; j++)
+        {
+            if (!f[op ^ 1][j])
+            {
+                continue;
+            }
+            int v = j * a[i] % 10;
+            if (f[op][v] < f[op ^ 1][j] + log(a[i]))
+            {
+                f[op][v] = f[op ^ 1][j] + log(a[i]);
+                b[op][v] = b[op ^ 1][j];
+                b[op][v].set(i);
+            }
+            else if (f[op][v] == f[op ^ 1][j] + log(a[i]) && b[op ^ 1][j].count() + 1 >= b[op][v].count())
+            {
+                f[op][v] = f[op ^ 1][j] + log(a[i]);
+                b[op][v] = b[op ^ 1][j];
+                b[op][v].set(i);
+            }
+        }
+        op ^= 1;
+    }
+    if (b[op ^ 1][m].none())
+    {
+        cout << "-1";
+    }
+    else
+    {
+        multiset<int> res;
+        cout << b[op ^ 1][m].count() << "\n";
+        for (int i = 1; i <= n; i++)
+        {
+            if (b[op ^ 1][m][i])
+            {
+                res.insert(a[i]);
+                // cout << a[i] << ' ';
+            }
+        }
+        for (int i : res)
+            cout << i << ' ';
+        cout << endl;
+    }
+    return 0;
+}