update

src/U206625/U206625_myself.cpp

@@ -0,0 +1,27 @@
+#include <algorithm>
+#include <iostream>
+#include <string>
+
+using std::cin, std::cout, std::string, std::for_each_n;
+typedef unsigned long long ull;
+
+static const size_t MOD {998244353}, MAX_N {300000+5};
+static string s;
+static size_t left_dp[MAX_N], last_left[MAX_N], unused_left_num, ans;
+static ull stk[MAX_N];
+
+int main(){
+    cin>>s;
+
+    for(size_t i {0};i<s.size();i++){
+        if(s[i]=='('){
+            stk[unused_left_num++]=i;
+        }else if(unused_left_num>0){
+            last_left[i] = stk[--unused_left_num];
+            cout<<(last_left[i]-1)<<"--\n";
+            left_dp[i] = (left_dp[last_left[i]-1] + last_left[i]+1) % MOD;
+            ans = (ans + left_dp[i] * (s.size() - i)) % MOD ;
+        }
+    }
+    cout<<ans<<'\n';
+}