A13819. Lonely Numbers
编程题
普及/提高-
知识点
题目描述
In number world, two different numbers are friends if they have a lot in common, but also each one has unique perks.
More precisely, two different numbers $a$ and $b$ are friends if $gcd(a,b)$ , $\frac{a}{gcd(a,b)}$ , $\frac{b}{gcd(a,b)}$ can form sides of a triangle.
Three numbers $a$ , $b$ and $c$ can form sides of a triangle if $a + b > c$ , $b + c > a$ and $c + a > b$ .
In a group of numbers, a number is lonely if it doesn't have any friends in that group.
Given a group of numbers containing all numbers from $1, 2, 3, ..., n$ , how many numbers in that group are lonely?
More precisely, two different numbers $a$ and $b$ are friends if $gcd(a,b)$ , $\frac{a}{gcd(a,b)}$ , $\frac{b}{gcd(a,b)}$ can form sides of a triangle.
Three numbers $a$ , $b$ and $c$ can form sides of a triangle if $a + b > c$ , $b + c > a$ and $c + a > b$ .
In a group of numbers, a number is lonely if it doesn't have any friends in that group.
Given a group of numbers containing all numbers from $1, 2, 3, ..., n$ , how many numbers in that group are lonely?
输入格式
The first line contains a single integer $t$ $(1 \leq t \leq 10^6)$ - number of test cases.
On next line there are $t$ numbers, $n_i$ $(1 \leq n_i \leq 10^6)$ - meaning that in case $i$ you should solve for numbers $1, 2, 3, ..., n_i$ .
On next line there are $t$ numbers, $n_i$ $(1 \leq n_i \leq 10^6)$ - meaning that in case $i$ you should solve for numbers $1, 2, 3, ..., n_i$ .
输出格式
For each test case, print the answer on separate lines: number of lonely numbers in group $1, 2, 3, ..., n_i$ .
输入输出样例
输入 #1
3 1 5 10
输出 #1
1 3 3
说明/提示
For first test case, $1$ is the only number and therefore lonely.
For second test case where $n=5$ , numbers $1$ , $3$ and $5$ are lonely.
For third test case where $n=10$ , numbers $1$ , $5$ and $7$ are lonely.
For second test case where $n=5$ , numbers $1$ , $3$ and $5$ are lonely.
For third test case where $n=10$ , numbers $1$ , $5$ and $7$ are lonely.