• CodeForces


    A. Nephren gives a riddle
    time limit per test
    2 seconds
    memory limit per test
    256 megabytes
    input
    standard input
    output
    standard output
    What are you doing at the end of the world? Are you busy? Will you save us?

    Nephren is playing a game with little leprechauns.

    She gives them an infinite array of strings, f0... ∞.

    f0 is "What are you doing at the end of the world? Are you busy? Will you save us?".

    She wants to let more people know about it, so she defines fi =  "What are you doing while sending "fi - 1"? Are you busy? Will you send "fi - 1"?" for all i ≥ 1.

    For example, f1 is

    "What are you doing while sending "What are you doing at the end of the world? Are you busy? Will you save us?"? Are you busy? Will you send "What are you doing at the end of the world? Are you busy? Will you save us?"?". Note that the quotes in the very beginning and in the very end are for clarity and are not a part of f1.

    It can be seen that the characters in fi are letters, question marks, (possibly) quotation marks and spaces.

    Nephren will ask the little leprechauns q times. Each time she will let them find the k-th character of fn. The characters are indexed starting from 1. If fn consists of less than k characters, output '.' (without quotes).

    Can you answer her queries?

    Input

    The first line contains one integer q (1 ≤ q ≤ 10) — the number of Nephren's questions.

    Each of the next q lines describes Nephren's question and contains two integers n and k (0 ≤ n ≤ 105, 1 ≤ k ≤ 1018).

    Output

    One line containing q characters. The i-th character in it should be the answer for the i-th query.

    Examples
    input
    3
    1 1
    1 2
    1 111111111111
    output
    Wh.
    input
    5
    0 69
    1 194
    1 139
    0 47
    1 66
    output
    abdef
    input
    10
    4 1825
    3 75
    3 530
    4 1829
    4 1651
    3 187
    4 584
    4 255
    4 774
    2 474
    output
    Areyoubusy     


    题目链接

    分析
    fi由5部分拼接而成,预处理长度,因为限制了k的范围,所以只用处理到长度1e18就好。然后根据n和k递归查找所在位子的具体字符。

    #include<iostream>
    #include<cstdio>
    #include<cmath>
    #include<cstdlib>
    #include<algorithm>
    #include<cstring>
    #include <queue>
    using namespace std;
    typedef long long LL;
    const int maxn = 1e5+5;
    const int mod = 772002+233;
    typedef pair<int,int> pii;
    #define X first
    #define Y second
    #define pb push_back
    #define mp make_pair
    #define ms(a,b) memset(a,b,sizeof(a))
    char f0[100]={"What are you doing at the end of the world? Are you busy? Will you save us?"};
    char t[100] ={"What are you doing while sending ""? Are you busy? Will you send ""?"};
    char t1[50]={"What are you doing while sending ""};
    char t2[50]={""? Are you busy? Will you send ""};
    char t3[5]={""?"};
    LL len[100];
    int l1,l2,l3,tot;
    void init(){
        l1=strlen(t1),l2=strlen(t2),l3=strlen(t3);
        len[0]=strlen(f0);
        
        int i;
        for(i=1;i<maxn;i++){
            len[i]=68+2*len[i-1];
            if(len[i]>=1e18) break;
        }
        tot=i;
    }
    char dfs(int n,LL k){
        if(n<=tot&&k>len[n]) return '.';
        else{
            if(n==0) return f0[k-1];
            else{
                if(k<=l1) return t1[k-1];
                if(n>tot || k<=l1+len[n-1]) return dfs(n-1,k-l1);
                if(k<=l1+len[n-1]+l2) return t2[k-1-(l1+len[n-1])];
                if(k<=l1+len[n-1]*2+l2) return dfs(n-1,k-(l1+len[n-1]+l2));
                return t3[k-1-(l1+len[n-1]*2+l2)];
            }
        }
    }
    int main(){
    //    freopen("in.txt","r",stdin);
        init();
        int n,q;
        LL k;
        cin>>q;
        while(q--){
            cin>>n>>k;
            cout<<dfs(n,k);
        }
    
        return 0;
    }
    
    
    


  • 相关阅读:
    HDU--2191 汶川地震购米(多重背包)
    PKU--1267 Cash Machine(多重背包)
    背包问题之多重背包
    NYOJ--311(完全背包)
    HDU--1114 Piggy-Bank(完全背包)
    MySQL的if,case语句
    测试一下MarkDown
    ThreadPoolExecutor介绍
    CountDownLatch的使用
    java中的信号量Semaphore
  • 原文地址:https://www.cnblogs.com/fht-litost/p/8551298.html
Copyright © 2020-2023  润新知