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  1.  
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4. #define ll long long
  5. #define endl '\n'
  6. ll N = 1e9+7;
  7. ll oo =1e13;
  8. const ll maxx = 1000000 + 3;
  9. ll n,k=0,q,x,y,z,l,r,mid,ans;
  10. string s1,s2;
  11. ll go(ll ind,ll c) {
  12.     if (ind== s2.size()) {
  13.         if (c==ans)return 1;
  14.         return 0;
  15.     }
  16.     ll res=0;
  17.     if (s2[ind]=='+')res += go(ind+1,c+1);
  18.     else if (s2[ind]=='-')res += go(ind+1,c-1);
  19.     else if (s2[ind]=='?') {
  20.         res += go(ind+1,c-1)+go(ind+1,c+1);
  21.     }
  22.     return res;
  23. }
  24. void solve() {
  25.     ll qcnt=0;
  26.     cin>>s1>>s2;
  27.     for (char s :s1) {
  28.         if (s=='+')ans++;
  29.         else ans--;
  30.     }
  31.  
  32.     for (char s :s2) {
  33.         if (s=='?') qcnt++;
  34.         else if (s=='+')k++;
  35.         else k--;
  36.     }
  37.     if (qcnt==0) {
  38.         if (ans==k) cout << 1;
  39.         else cout << 0;
  40.     }else {
  41.         double prob = go(0,0) / pow(2.0, qcnt);
  42.         cout << fixed << setprecision(12) << prob << endl;
  43.     }
  44. }
  45. int main() {
  46.     ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
  47.     ll t=1 ;
  48.     // cin >>t;
  49.     while (t--) {
  50.         ans=0;
  51.         solve();
  52.     }
  53. }
Success #stdin #stdout 0.01s 5292KB
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stdin
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+-+-
+-??
stdout
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0.500000000000
https://ideone.com/qQE1Fh
language:
C++ (gcc 8.3)
created:
8 hours ago
visibility:
public

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