zoukankan      html  css  js  c++  java
  • HDU 2841 Visible Trees

    Visible Trees

    Time Limit: 1000ms
    Memory Limit: 32768KB
    This problem will be judged on HDU. Original ID: 2841
    64-bit integer IO format: %I64d      Java class name: Main
    There are many trees forming a m * n grid, the grid starts from (1,1). Farmer Sherlock is standing at (0,0) point. He wonders how many trees he can see.

    If two trees and Sherlock are in one line, Farmer Sherlock can only see the tree nearest to him.
     

    Input

    The first line contains one integer t, represents the number of test cases. Then there are multiple test cases. For each test case there is one line containing two integers m and $n(1leq m, nleq 100000)$
     

    Output

    For each test case output one line represents the number of trees Farmer Sherlock can see.
     

    Sample Input

    2
    1 1
    2 3

    Sample Output

    1
    5

    Source

     
    解题:容斥原理
     1 #include <bits/stdc++.h>
     2 using namespace std;
     3 typedef long long LL;
     4 const int maxn = 200010;
     5 vector<int>g[maxn];
     6 void init(){
     7     for(int i = 2; i < maxn; ++i){
     8         for(int j = 1; i*j < maxn; ++j)
     9             g[i*j].push_back(i);
    10     }
    11 }
    12 int main(){
    13     int kase,n,m;
    14     init();
    15     scanf("%d",&kase);
    16     while(kase--){
    17         scanf("%d%d",&n,&m);
    18         LL ret = 0;
    19         for(int i = 2; i <= n; ++i){
    20             int cnt = 0,ans = 0;
    21             for(int j = 1,t = g[i].size();j < (1<<t); ++j){
    22                  LL tmp = 1;
    23                  for(int k = cnt = 0; k < t; ++k){
    24                     if((j>>k)&1){
    25                         cnt++;
    26                         tmp *= g[i][k];
    27                     }
    28                 }
    29                 if(cnt&1) ans += m/tmp;
    30                 else ans -= m/tmp;
    31             }
    32             ret += m - ans;
    33         }
    34         printf("%I64d
    ",ret + m);
    35     }
    36     return 0;
    37 }
    View Code
  • 相关阅读:
    C段/旁站,子域名爆破的概念
    Linux USB Printer Gadget Driver
    Multifunction Composite Gadget
    PXA2xx SPI on SSP driver HOWTO
    SPI用户空间API
    Linux内核SPI支持概述
    Industrial I/O
    I2C设备驱动程序从用户空间绑定控制(旧内核)
    I2C 10-bit 地址
    Slave I2C
  • 原文地址:https://www.cnblogs.com/crackpotisback/p/4846909.html
Copyright © 2011-2022 走看看