Nowcoder: 81605I

Riffle Shuffle

Nowcoder/81605I.cpp

@@ -0,0 +1,74 @@
+/**
+ * @file 81605I.cpp
+ * @author Macesuted ([email protected])
+ * @date 2024-08-15
+ *
+ * @copyright Copyright (c) 2024
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+#define maxn 1000005
+
+int a[maxn], b[maxn], pos[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+    for (int i = 1; i <= n; i++) cin >> a[i];
+
+    auto calc = [&](void) {
+        int cnt = 0;
+        for (int i = 1; i < n; i++) cnt += (a[i] + 1 == a[i + 1]);
+        return cnt;
+    };
+
+    vector<string> ans;
+    while (calc() < n - 1) {
+        for (int i = 1; i <= n; i++) pos[b[i] = a[i]] = i;
+        string op(n, 'A');
+        int cnt = 0;
+        for (int l = 1, r, t = 0; l <= n; l = r + 1, t = !t) {
+            r = l;
+            while (r < n && pos[r + 1] > pos[r]) r++;
+            if (t)
+                for (int i = l; i <= r; i++) op[pos[i] - 1] = 'B', cnt++;
+        }
+        ans.push_back(op);
+        for (int i = n; i; i--)
+            for (int j = 1; j < i; j++)
+                if (op[j - 1] > op[j]) swap(a[j], a[j + 1]), swap(op[j - 1], op[j]);
+    }
+    reverse(ans.begin(), ans.end());
+
+    cout << ans.size() << endl;
+    for (auto i : ans) cout << i << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}