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Codeforces Hello2015第一题Cursed Query

时间:2017-07-22 23:44:01      阅读:220      评论:0      收藏:0      [点我收藏+]

标签:integer   pop   watch   code   i++   printf   using   return   n+1   

英文题面:

De Prezer loves movies and series. He has watched the Troy for like 100 times and also he is a big fan of Supernatural series.So, he did some researches and found a cursed object which had n lights on it and initially all of them were turned off.Because of his love to the Troy, he called that object Troy.

He looked and saw a note on it in Khikulish (language of people of Khikuland): "Ma in hame rah umadim, hala migi ... ? ... Mage man De Prezer am k mikhay mano ... ? .... Man se sale ... To boro .... beshur manam miram ... o mishuram".

He doesn‘t know Khikulish, so just ignored the note and tested the Troy.

He realized that the light number i stays turned on for exactly ai seconds, and then it turns itself off (if it is turned on, in time t, in time t?+?ai?-?1 it will be turned on, but on time t?+?ai it won‘t be) and the next light will be turned on (if i?<?n, next light is the light number i?+?1, otherwise it is light with number 1).

For example if n?=?2 and we turn on the first light in time 0, it will be turned on in hole interval [0,?a1) and in hole interval [a1,?a1?+?a2) the second light will be turned on and so on.

In time 0 he turns on the light number 1.

De Prezer also loves query.So he gives you q queries.In each query he will give you integer t (the time a revengeful ghost attacked him) and you should print the number of the light that is turned on, in time t.

Input

The first line of input contains two integers n and q.

The second line contains n space separated integers, a1,?a2,?...,?an .

The next q lines, each line contains a single integer t .

1?≤?n,?q?≤?105

1?≤?ai?≤?109

1?≤?t?≤?1018

Output

For each query, print the answer in one line.

 

        就是说有n盏灯,然后给出每盏灯亮的时间(第一盏从时刻0開始亮直到时刻0+a1-1,第二盏在a1时刻亮起,以此类推),然后题目给出q组询问,询问内容是一个t,要你给出t时刻亮的时哪盏灯。

我的做法是每次询问就来一次二分查找,log2n的复杂度再盛上10^5次询问能够接受。

Sample test(s):

Input
5 7
1 2 3 4 5
1
2
3
7
14
15
16

 

Output
2
2
3
4
5
1
2

 

        这组測试数据还是业界良心的。爆出了可能出错的坑,这一串灯是循环的首尾相接地亮。所以那个t是10^18这么大,要取模。

 

代码:

 

#include <iostream>
#include<stdio.h>
using namespace std;

long long int start[100005];//每盏灯開始亮时刻
long long int End[100005];//每盏灯亮完时刻
int n,q,a;
long long int t;

int work(long long int ask)//每次二分查找函数
{
    int p=1;
    int p1=1;
    int p2=n;
    while(ask<start[p]||ask>End[p])
    {
        p=(p1+p2)/2;
        if(ask>=start[p]&&ask<=End[p])
        {
            break;
        }else if(ask>=start[p1]&&ask<=End[p1])
        {
            p=p1;
            break;
        }else if(ask>=start[p2]&&ask<=End[p2])
        {
            p=p2;
            break;
        }else if(ask<start[p]&&ask>End[p1])
        {
            p2=p;
        }else if(ask>End[p]&&ask<start[p2])
        {
            p1=p;
        }
    }

    return p;//p就是那盏灯
}

int main()
{
    scanf("%d%d",&n,&q);
    start[1]=0;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&a);
        End[i]=start[i]+a-1;
        start[i+1]=start[i]+a;
    }
    while(q--)
    {
        scanf("%I64d",&t);
        printf("%d\n",work(t%start[n+1]));
    }
    return 0;
}


 

Codeforces Hello2015第一题Cursed Query

标签:integer   pop   watch   code   i++   printf   using   return   n+1   

原文地址:http://www.cnblogs.com/lytwajue/p/7222928.html

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