题解

#include <stdio.h>
#include <stdlib.h>

int cmp(const void a, const void b) {
return ((int)b - (int)a);
}

int main() {
int n, k;
scanf("%d %d", &n, &k);

int a[1000];
int sum = 0;
int mods[1000], cnt = 0;

for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    int r = a[i] % 3;
    if (r == 0) {
    } else {
        mods[cnt++] = r; 
        sum += r;
    }
}
qsort(mods, cnt, sizeof(int), cmp);
for (int i = 0; i < cnt && k > 0; i++, k--) {
    sum -= mods[i];
}
printf("%d\n", sum);
return 0;

}