update atcoder 175 f

Author: bira37

AtCoder/ABC175/F.cpp

@@ -88,7 +88,7 @@ tuple<string, string> calc(string a, string b)
  return mt(s, t);
 }
 
-bool palin(string s)
+bool palin(string &s)
 {
  string t = s;
  reverse(all(t));
@@ -111,22 +111,24 @@ void solution()
  set<pair<int, pss>> pq;
  for (int i = 0; i < n; i++)
  {
- dist[mp(s[i], "")] = c[i];
- dist[mp("", s[i])] = c[i];
+ if (!dist.count(mp(s[i], "")))
+ dist[mp(s[i], "")] = INF;
+ if (!dist.count(mp("", s[i])))
+ dist[mp("", s[i])] = INF;
+ dist[mp(s[i], "")] = min(dist[mp(s[i], "")], c[i]);
+ dist[mp("", s[i])] = min(dist[mp("", s[i])], c[i]);
  pq.insert(mp(c[i], mp("", s[i])));
  pq.insert(mp(c[i], mp(s[i], "")));
  }
 
- int ans = INF;
  while (!pq.empty())
  {
  int cur = pq.begin()->ff;
  string pre = pq.begin()->ss.ff;
  string suf = pq.begin()->ss.ss;
  pq.erase(pq.begin());
-
- if (palin(pre + suf))
- ans = min(ans, cur);
+ if (dist[mp(pre, suf)] != cur)
+ continue;
 
  //cout << "dist " << pre << " | " << suf << " = " << cur << endl;
  if (pre == "")
@@ -167,14 +169,18 @@ void solution()
  }
  }
 
+ int ans = INF;
  for (auto state : dist)
  {
  string a = state.ff.ff;
  string b = state.ff.ss;
- if (palin(a + b))
+ bool ok = false;
+ ok |= (a.size() == 0 && b.size() == 0);
+ ok |= (a.size() == 0 && palin(b));
+ ok |= (b.size() == 0 && palin(a));
+ if (ok)
  ans = min(ans, state.ss);
  }
-
  cout << (ans < INF ? ans : -1) << endl;
 }
 
@@ -189,4 +195,3 @@ int32_t main()
  while (t--)
  solution();
 }
-