最接近整除 integer

Question

Example.

int a = 254;
int b = 25;

int c = (closest integer to `a` that is divisible by `b`)

How can I find the integer c ? The result of that example is c = 250 .

Answer 1

There are two cases to consider:

1. The closest integer that is less than or equal to a :

    int c1 = a - (a % b);

2. The closest integer that is greater than a :

    int c2 = (a + b) - (a % b);

Then we need to check which is closer to a and return that:

int c;
if (a - c1 > c2 - a) {
    c = c2;
} else {
    c = c1;
}

So we could create a closestInteger() method like this:

static int closestInteger(int a, int b) {
    int c1 = a - (a % b);
    int c2 = (a + b) - (a % b);
    if (a - c1 > c2 - a) {
        return c2;
    } else {
        return c1;
    }
}

Example:

System.out.println(closestInteger(254, 25));
System.out.println(closestInteger(9, 5));

Output:

250
10

Answer 2

You have to check on both sides of a . So we set 'c1' to the closest integer below (or equal to) a , and c2 to be the closest integer above it. Then compare the differences. If c1 is closer to a , set c to c1 , otherwise c2 .

int c1 = a - (a % b);
int c2 = c1 + b;
int c = a - c1 < c2 - a ? c1 : c2;

Answer 3

Closest below: int c = (a/b)*b;

Since a and b are both int. The division a/b will truncate to the nearest in value (10). Then multiplying the result by b will give what you are looking for.

Or

Closest either way:

int c = Math.round((float)a/b))*b;

Since a is cast as float the answer will be a float and rounding goes to the nearest int.

Answer 4

If you don't mind going to the next highest integer when there is a tie (eg closest integer to 6 that is a multiple of 4 becomes 8 and not 4), then you can use this simple formula. No comparisons are needed.

int c = (a + b/2)/b * b;  // closest integer to `a` that is divisible by `b`

All calculations are done with integer arithmetic (fractions are discarded).

Answer 5

 var nums = [0, 9, 26, 39]; for (var i=0 ; i<nums.length;i++){ const mod = nums[i]%3; if(mod!=0){ console.log("Closest Multiple: "+(3*Math.round(nums[i]/3))) }else{ console.log("Closest multiple: "+nums[i]) } }

Answer 6

static void checkDivisibility(int i,int j) {
    int mod = i % j;
    if (mod == 0) {
        System.out.println(i+ " is divisible by 13 ");

    } else {
        if (mod >= 7) {
            i = (i + (j - mod));
        } else {
            i = i - mod;
        }
        System.out.println(i+" is the nearest divisible ");
    }
}

Call this method : checkDivisibility(40,13); Output : 39 is the nearest divisible

Answer 7

• Closet number less than a int c1 = a - (a % b);

• Closet number greater than a int c2 = a + (b - (a%b))

Now compare which one has less difference from a

int d1 = a - c1;

int d2 = c2 - a;

if(d1 > d2)//closest number is c2

else //closest number is c1

Answer 8

int actual; // for example 23
int divisibleBy; // for example 8
int result = actual + divisibleBy - 1 & -divisibleBy; // result is 24