Can't Wait for Holiday [AtCoder Beginner Contest 146 A]

https://atcoder.jp/contests/abc146/tasks/abc146_a

解説

https://atcoder.jp/contests/abc146/submissions/8629033

SUN,MON,TUE,WED,THU,FRI,SATを0,1,2,3,4,5,6と変換して考えてみよう。
すると、答えは7-S'となる。
文字列だと差を出しにくいので、数値に変換して考える。

string S;
string week[7] = { "SUN","MON","TUE","WED","THU","FRI","SAT" };
//---------------------------------------------------------------------------------------------------
void _main() {
    cin >> S;
    rep(i, 0, 7) if (week[i] == S) {
        int ans = 7 - i;
        cout << ans << endl;
        return;
    }
}