Problems: Expressions That Bite

Maria runs a locker room where every code is exactly three digits. Her label printer wants the digits one at a time.

Input. One line with one integer n.

Output. One line with the three digits of n, separated by single spaces.

Constraints. 100 <= n <= 999.

Sample. Input 407 gives 4 0 7.

#include <stdio.h>

int main(void)
{
    int n = 0;
    scanf("%d", &n);

    /* Hundreds with /, units with %, and the middle one needs both. */

    return 0;
}

Zara is testing a scheduler that fires a job every d ticks, and wants a yes or no answer for a given tick.

Input. One line with two integers n and d.

Output. One line with 1 if d divides n exactly, otherwise 0.

Constraints. -1000000000 <= n <= 1000000000, and 1 <= d <= 1000000000.

Sample. Input 91 7 gives 1. Input -91 6 gives 0.

#include <stdio.h>

int main(void)
{
    int n = 0;
    int d = 0;
    scanf("%d %d", &n, &d);

    /* A comparison is worth 1 or 0, so print it with %d. No if needed. */

    return 0;
}

Maria's till closes with five sales on the slip, and she wants one running total built one sale at a time.

Input. One line with five integers. A sale may be negative, because a refund goes on the same slip.

Output. One line with their total.

Constraints. Each value is between -1000000 and 1000000.

Sample. Input 10 20 30 40 50 gives 150.

#include <stdio.h>

int main(void)
{
    int a = 0;
    int b = 0;
    int c = 0;
    int d = 0;
    int e = 0;
    scanf("%d %d %d %d %d", &a, &b, &c, &d, &e);

    int total = 0;
    /* Five += lines, one per value. */

    return 0;
}

David is writing the calendar check every project eventually needs. A year is a leap year when it divides by 4 and not by 100, or when it divides by 400.

Input. One line with one integer y.

Output. One line with 1 if y is a leap year, otherwise 0.

Constraints. 1 <= y <= 999999.

Sample. Input 2024 gives 1. Input 1900 gives 0. Input 2000 gives 1.

#include <stdio.h>

int main(void)
{
    int y = 0;
    scanf("%d", &y);

    /* Three remainders, two comparisons joined by &&, then one ||. */

    return 0;
}

Kenji wants to prove he can read a line the way C reads it. His teacher gives him five expressions and three numbers.

Input. One line with three integers a, b and c.

Output. Five lines, the values of a + b * c, a - b - c, a * b % c, a < b && b < c and a + b > c, in that order.

Constraints. -1000 <= a, b <= 1000, and 1 <= c <= 1000.

Sample. Input 2 3 4 gives the five lines 14, -5, 2, 1, 1.

#include <stdio.h>

int main(void)
{
    int a = 0;
    int b = 0;
    int c = 0;
    scanf("%d %d %d", &a, &b, &c);

    /* Type the five expressions exactly as written. Add no brackets. */

    return 0;
}

David is writing the smallest calculator anyone has ever shipped. It reads five numbers and evaluates a * b + c / d - e % d, exactly as C would.

Input. One line with five integers a, b, c, d and e.

Output. One line with the value of that expression.

Constraints. -1000 <= a, b, c, e <= 1000, and 1 <= d <= 1000.

Sample. Input 2 3 10 4 7 gives 5.

#include <stdio.h>

int main(void)
{
    int a = 0;
    int b = 0;
    int c = 0;
    int d = 0;
    int e = 0;
    scanf("%d %d %d %d %d", &a, &b, &c, &d, &e);

    /* One expression, typed exactly as the statement writes it. */

    return 0;
}

Maria's image tool stores a colour as three bytes packed into one number, then has to take them apart again.

Input. One line with three integers r, g and b.

Output. Two lines. The first is the packed value: red in bits 16 to 23, green in bits 8 to 15, blue in bits 0 to 7. The second is r, g and b read back out of it, separated by single spaces.

Constraints. 0 <= r, g, b <= 255.

Sample. Input 200 130 40 gives 13140520, then 200 130 40.

#include <stdio.h>

int main(void)
{
    unsigned int r = 0;
    unsigned int g = 0;
    unsigned int b = 0;
    scanf("%u %u %u", &r, &g, &b);

    /* Pack with two shifts and two ors. Unpack with shifts and 255u. */

    return 0;
}

Amara is reading an old instrument format where every byte arrived with its two four bit halves the wrong way round.

Input. One line with one integer b.

Output. One line with b after its top four bits and its bottom four bits have exchanged places.

Constraints. 0 <= b <= 255.

Sample. Input 195 gives 60. Input 16 gives 1.

#include <stdio.h>

int main(void)
{
    unsigned int b = 0;
    scanf("%u", &b);

    /* Two halves: one moves up four places, the other moves down four. */

    return 0;
}

Kenji's control board holds 32 switches in one number. A maintenance command names one switch to turn on, one to turn off and one to flip.

Input. One line with four integers: the starting value v, then the bit numbers i, j and k.

Output. Three lines: the value after setting bit i, then after clearing bit j, then after toggling bit k. Each step starts from the value the previous one left.

Constraints. 0 <= v <= 4294967295, and 0 <= i, j, k <= 31.

Sample. Input 0 3 3 5 gives the three lines 8, 0, 32.

#include <stdio.h>

int main(void)
{
    unsigned int v = 0;
    unsigned int i = 0;
    unsigned int j = 0;
    unsigned int k = 0;
    scanf("%u %u %u %u", &v, &i, &j, &k);

    /* Three idioms, in order: set, clear, toggle. Print after each one. */

    return 0;
}

Maria's stock import left some counts negative. A limit check that stores its limit as an unsigned int has answered no for every one of them.

Input. One line with two integers: a signed count and a limit, which your program must read into an unsigned int.

Output. Two lines: the value of count < limit with the limit left unsigned, then the value of the same comparison done in signed arithmetic.

Constraints. -1000000 <= count <= 1000000, and 0 <= limit <= 1000000.

Sample. Input -1 1 gives 0, then 1.

#include <stdio.h>

int main(void)
{
    int count = 0;
    unsigned int limit = 0;
    scanf("%d %u", &count, &limit);

    /* First line: no cast. Second line: one cast on the limit. */

    return 0;
}