CodeForces597ADivisibility(数学)

来源:互联网 发布:暗影精灵3 新机优化 编辑:程序博客网 时间:2024/06/01 07:53
Description
Find the number of k-divisible numbers on the segment [a, b]. In other words you need to find the number of such integer values x that a ≤ x ≤ b and x is divisible by k.

Input
The only line contains three space-separated integers k, a and b (1 ≤ k ≤ 1018; - 1018 ≤ a ≤ b ≤ 1018).

Output
Print the required number.

Sample Input
Input
1 1 10
Output
10
Input
2 -4 4
Output

5

代码:

#include<iostream>#include<stdio.h>#include<math.h>#include<algorithm>#include<string.h>using namespace std;int main(){long long i,k,a,b;while(scanf("%lld %lld %lld",&k,&a,&b)!=EOF){long long ans,l,o;l=abs(a/k);o=abs(b/k);if(a<=0&&b>=0){ans=o+l+1;}else if(a<0&&b<0){ans=l-abs((b+1)/k);}else {ans=abs(o-(a-1)/k);}printf("%lld\n",ans);}return 0;}


题意:给你一个区域,问这里面有多少个可以对k整除的数

思路:注意分情况讨论,三种情况。符号相同时注意对小数-1计算,因为小数可能也可以对该数整除。(这道题分类很重要,分错类了很容易出错)

0 0