T1 81029noip simulation competition T1

1,Borrow Books

[Problem description]

Dilhao has a total of N textbooks, each of which has a difficulty value. Each time he answers a question, he will pick two textbooks for reference. If the difficulty of the two books is different, the more complicated the questions that result from dilhao, that is,The complexity of a question equals the absolute value of the difficulty difference between the two books.

This is the turn of ldxxx. He wants to ask about the problem by using the m book. dilhao wants to know if ldxxx givesChoose the two books with the least difficulty in the m book.Question, then the question from ldxxxMaximum complexityWhat is it?

[Input format]

The first line is N and M.

In the next n rows, each line has an integer "AI", indicating the difficulty of the I-th book.

[Input format]

An integer is the maximum complexity of a question produced by ldxxx.

[Input example]

6 3

5

7

1

17

13

10

[Output example]

7

[Example]

Dilhao gave ldxxx three books with difficulty 1, 10, and 17, ldxxx selected two books with difficulty 10 and 17, and the complexity of the question was 7;

If dilhao provides any other three books, the minimum difficulty between the two books is less than 7, so the greatest complexity of ldxxx is 7.

[Data description]

For 30% of data: 2 <= n <= 20;

For 60% of data: 2 <= n <= 1000;

For 100% of data: 2 <= n <= 100000, 2 <= m <= N, 0 <= AI <= 1000000000.

Ideas:

Question at a glance

For the original array, we can divide it

Then, give two answers.

Scan the original sequence for verification.

Code:

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#define rii register int i#define rij register int jusing namespace std;int n,m,x[100005],cha[100005];bool cmp(int lk,int kl){    return lk<kl;}bool check(int val){    int jsq=0,ch=0;    for(rii=1;i<n;i++)    {        ch+=cha[i];        if(ch>=val)        {            jsq++,ch=0;        }    }    if(jsq>=m-1)    {        return true;    }    return false;}int main(){    freopen("margin.in","r",stdin);    freopen("margin.out","w",stdout);    scanf("%d%d",&n,&m);    int r=0,l=0;    for(rii=1;i<=n;i++)    {        scanf("%d",&x[i]);        r=max(r,x[i]);    }    sort(x+1,x+n+1,cmp);    for(rii=1;i<n;i++)    {        cha[i]=x[i+1]-x[i];    }    while(l<=r)    {        if(r-l==1)        {            if(check(r)==true)            {                l=r;            }            break;        }        int mid=(l+r)/2;        if(check(mid)==true)        {            l=mid;        }        else        {            r=mid;        }    }    cout<<l;}

 

T1 81029noip simulation competition T1