826. 单链表

https://www.acwing.com/problem/content/submission/code_detail/7357618/

AcWing/826/826.cpp

@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int m, k, x, t;
+char op;
+list<int> a;
+list<int>::iterator it[100005];
+
+int main() {
+    cin >> m;
+    while (m--) {
+        cin >> op;
+        if (op == 'H') {
+            cin >> x;
+            a.push_front(x);
+            it[++t] = a.begin();
+        } else if (op == 'D') {
+            cin >> k;
+            if (k == 0) {
+                a.pop_front();
+            } else {
+                auto itk = it[k];
+                a.erase(++itk);
+            }
+        } else {
+            cin >> k >> x;
+            auto itk = it[k];
+            it[++t] = a.insert(++itk, x);
+        }
+    }
+    for (int i : a) {
+        cout << i << ' ';
+    }
+    cout << endl;
+    return 0;
+}