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  1. #include<bits/stdc++.h>
  2. #define ll long long
  3. using namespace std;
  4. ll n,dp[100005][2],a[100005],b[100005],ans = 0;
  5. const ll mod = 1e9 + 7;
  6. int main()
  7. {
  8.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  9.     memset(dp, 0, sizeof dp);
  10.     cin >> n;
  11.     for(int i = 1; i <= n; i++)
  12.         cin >> a[i];
  13.     for(int i = 2; i <= n; i++)
  14.         cin >> b[i];
  15.     dp[0][0] = 1;
  16.     dp[0][1] = 0;
  17.     for(int i = 1; i <= n; i++)
  18.     {
  19.         dp[i][0] = (dp[i-1][0]*(a[i] + b[i])%mod + dp[i-1][1]*(a[i]+b[i]-1)%mod)%mod;
  20.         dp[i][1] = (dp[i-1][0]*b[i]%mod + dp[i-1][1]*b[i+1]%mod)%mod;
  21.         cout << dp[i][0] << ' ' << dp[i][1] << '\n';
  22.     }
  23.     ans = dp[n][0] + dp[n][1];
  24.     ans%=mod;
  25.     cout << ans;
  26. }
  27.  
Success #stdin #stdout 0.01s 5288KB
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stdin 
Standard input is empty
stdout 
1
https://ideone.com/doJbXA
language:
C++14 (gcc 8.3)
created:
78 days ago
visibility:
public

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