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hdu 3530 (单调队列)

Subsequence

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 4441    Accepted Submission(s): 1457

Problem Description
There is a sequence of integers. Your task is to find the longest subsequence that satisfies the following condition: the difference between the maximum element and the minimum element of the subsequence is no smaller than m and no larger than k.
 
Input
There are multiple test cases. For each test case, the first line has three integers, n, m and k. n is the length of the sequence and is in the range [1, 100000]. m and k are in the range [0, 1000000]. The second line has n integers, which are all in the range [0, 1000000]. Proceed to the end of file.
 
Output
For each test case, print the length of the subsequence on a single line.
 
Sample Input
5 0 0
1 1 1 1 1
5 0
3 1 2 3 4 5
Sample Output
5
4
用两个单调队列维护最大值和最小值
#include<iostream>#include<cstdio>#include<cstring>#include<string>#include<vector>#include<stack>#include<queue>#include<set>#include<cmath>#include<map>#include<algorithm>using namespace std;int p[101010];int mmax[101010],mmin[101010];int main(){    int n,m,k;    while(cin>>n>>m>>k){        for(int i=1;i<=n;i++) scanf("%d",p+i);        int head1,tail1,head2,tail2,be=1,mm=0;        head1=tail1=0;        head2=tail2=0;        for(int i=1;i<=n;i++){            while(head1<tail1&&p[mmax[tail1-1]]<p[i]) tail1--;//维护单调递增            while(head2<tail2&&p[mmin[tail2-1]]>p[i]) tail2--;//维护单调递减            mmax[tail1++]=i;            mmin[tail2++]=i;            while(head1<tail1&&head2<tail2&&p[mmax[head1]]-p[mmin[head2]]>k){                if(mmax[head1]<mmin[head2]) be=mmax[head1++]+1;                else be=mmin[head2++]+1;            }            if(head1<tail1&&head2<tail2&&p[mmax[head1]]-p[mmin[head2]]>=m){                mm=max(mm,i-be+1);            }        }        cout<<mm<<endl;    }}

 

 

hdu 3530 (单调队列)