aoc 2020 day 5 revengeance edition

parts_1_and_2.c

#include <stdio.h>

int main(void) {
    int a, i, c, t = 0, m = 0xfff, M = 0;
    for (;;) {
        for (a = i = 0; i < 11; i++) a |= (~(c = getchar()) & 4) << 7 >> i;
        if (c == EOF) break;
        if (a > M) M = a;
        if (a < m) m = a;
        t += a;
    }
    printf("%d\n%d\n", M, (M * M + M - m * m + m >> 1) - t);
}