Codeforces #247 (Div. 2) A. Black Square

水题一道，４分钟ＡＣ

代码如下：

#include <cstdio>#include <iostream>#include <algorithm>#define MAXN 100010#define ll long longusing namespace std;int a[MAXN];int main(void) {    for(int i=1; i<=4; ++i) {        cin >> a[i];    }    string str;    cin >> str;    ll sum = 0;    for(int i=0; i<str.size(); ++i) {        sum += a[str[i]-'0'];    }    cout << sum << endl;    return 0;}