A - Contest Result Editorial by en_translator
If you are new to learning programming and do not know where to start, please try Problem A “Welcome to AtCoder” from practice contest. There you can find a sample code for each language.
Also, if you are not familiar with problems in programming contests, we recommend you to try some problems in “AtCoder Beginners Selection” (https://atcoder.jp/contests/abs).
Implement the following procedure.
- Receive the input.
- Prepare a variable ans, initializing it with \(0\).
- For each \(i\ (1\leq i \leq M)\), add \(A_{B_i}\) to ans.
- Print the value of ans.
For more specific implementation, see the sample codes below (in C++ and Python). Note that, depending on implementation, you may need to subtract \(1\) from \(B_i\) that you received from the input, since the indices start with \(0\) in many programming languages.
C++
#include<bits/stdc++.h>
using namespace std;
int main() {
int n, m;
cin >> n >> m;
vector<int> a(n), b(m);
for (int i = 0; i < n; i++) cin >> a[i];
for (int i = 0; i < m; i++) {
cin >> b[i];
--b[i];
}
int ans = 0;
for (int i = 0; i < m; i++) ans += a[b[i]];
cout << ans << endl;
}
Python
n, m = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
ans = 0
for i in range(0, m):
ans += a[b[i] - 1]
print(ans)
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