[BOJ] 16112 : 5차 전직

#include <cstdio>
#include <algorithm>
int n, k, a[300003];
long long r, s;
int main() {
    scanf("%d %d", &n, &k);
    for (int i = 0; i < n; i++) scanf("%d", &a[i]);
    std::sort(a, a+n);
    for (int i = n-1; i >= 0; i--) {
        if (i < k) r += s;
        s += (long long)a[i];
    }
    printf("%lld", r);
    return 0;
}