Problem:
Score : 100 points

Problem Statement

How many multiples of d are there among the integers between L and R (inclusive)?

Constraints

All values in input are integers.

1 \leq L \leq R \leq 100

1 \leq d \leq 100

Input

Input is given from Standard Input in the following format:

L R d

Output

Print the number of multiples of d among the integers between L and R (inclusive).

Sample Input 1

5 10 2

Sample Output 1

3

Among the integers between 5 and 10, there are three multiples of 2: 6, 8, and 10.

Sample Input 2

6 20 7

Sample Output 2

2

Among the integers between 6 and 20, there are two multiples of 7: 7 and 14.

Sample Input 3

1 100 1

Sample Output 3

100

Solution in C++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;

int cal(int x, int y, int z){
    return x * x + y * y + z * z + x * y + y * z + z * x;
}

int main(void){
    int n;
    cin >> n;
    vector<int> cnt(n + 1);
    for(int x = 1; x * x <= n; ++x){
        for(int y = 1; y * y + x * x <= n; ++y){
            for(int z = 1;; ++z){
                int v = cal(x, y, z);
                if(v <= n) ++cnt[v];
                else break;
            }
        }
    }
    for(int i = 1; i <= n; ++i) cout << cnt[i] << endl;
    return 0;
}