P4824 [USACO15FEB] Censoring S

https://www.luogu.com.cn/record/84303219

Luogu/P4824/P4824.cpp

@@ -0,0 +1,51 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <stack>
+#include <string>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e6 + 5;
+const int hash = 233333;
+
+int cnt;
+char st[N];
+std::string s, t;
+unsigned long long p = 1, h[N], t_hash;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> s >> t;
+
+    int n = s.size();
+    int m = t.size();
+    s = ' ' + s;
+
+    for (char c : t) {
+        t_hash = t_hash * hash + c;
+        p *= hash;
+    }
+
+    for (int i = 1; i <= n; i++) {
+        st[++cnt] = s[i];
+
+        h[cnt] = h[cnt - 1] * hash + s[i];
+
+        if (cnt >= m && h[cnt] - h[cnt - m] * p == t_hash) {
+            cnt -= m;
+        }
+    }
+
+    for (int i = 1; i <= cnt; i++) {
+        cout << st[i];
+    }
+
+    cout << endl;
+
+    return 0;
+}