View Compilation Error

0_0_30740771_2145.cpp: In function 'int main()':
0_0_30740771_2145.cpp:36:4: error: expected ',' or ';' before 'dp'
    dp[i+1]=(dp[i]+(a[i]*t)%mod+((t-1)*(dp[i]-dp[x[i]])%mod+mod)%mod)%mod;
    ^