A.简单dp. #include<bits/stdc++.h> using namespace std; ],dp[][] = {}; int main() { ios::sync_with_stdio(); cin >> n; ;i <= n;i++) cin >> a[i]; ; ;i <= n;i++) { ) { dp[i][] = dp[i-][]+; dp[i][] = dp[i-][]; } else { dp[i][] = dp[i-][];…