洛谷 P1886 滑动窗口 题解

每日一题 day26 打卡

Analysis

单调队列模板

对于每一个区间,有以下操作:

1、维护队首(就是如果你已经是当前的m个之前那你就可以被删了,head++)

2、在队尾插入(每插入一个就要从队尾开始往前去除冗杂状态)

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #define int long long
 6 #define maxn 1000000+10 
 7 using namespace std;
 8 inline int read() 
 9 {
10     int x=0;
11     bool f=1;
12     char c=getchar();
13     for(; !isdigit(c); c=getchar()) if(c=='-') f=0;
14     for(; isdigit(c); c=getchar()) x=(x<<3)+(x<<1)+c-'0';
15     if(f) return x;
16     return 0-x;
17 }
18 inline void write(int x)
19 {
20     if(x<0){putchar('-');x=-x;}
21     if(x>9)write(x/10);
22     putchar(x%10+'0');
23 }
24 int n,k;
25 int a[maxn];
26 int deque[maxn],deque_num[maxn];
27 inline void solve_min()
28 {
29     int head=1,tail=0;
30     for(int i=1;i<=n;i++)
31     {
32         while(head<=tail&&deque[tail]>=a[i]) tail--;
33         deque[++tail]=a[i];
34         deque_num[tail]=i;
35         while(head<=tail&&deque_num[head]<=i-k) head++;
36         if(i>=k)
37         {
38             write(deque[head]);
39             printf(" ");
40         }
41     }
42     printf("
");
43 }
44 inline void solve_max()
45 {
46     int head=1,tail=0;
47     for(int i=1;i<=n;i++)
48     {
49         while(head<=tail&&deque[tail]<=a[i]) tail--;
50         deque[++tail]=a[i];
51         deque_num[tail]=i;
52         while(head<=tail&&deque_num[head]<=i-k) head++;
53         if(i>=k)
54         {
55             write(deque[head]);
56             printf(" ");
57         }
58     }
59 }
60 signed main()
61 {
62     n=read();k=read();
63     for(int i=1;i<=n;i++) a[i]=read();
64     solve_min();
65     memset(deque,0,sizeof(deque));
66     memset(deque_num,0,sizeof(deque_num));
67     solve_max();
68     return 0;
69 }
70 /*
71 10 3
72 -94 21 24 73 38 77 11 73 9 -88 
73 
74 -94 21 24 38 11 11 9 -88 
75 24 73 73 77 77 77 73 73 
76 */

请各位大佬斧正(反正我不认识斧正是什么意思)

原文地址:https://www.cnblogs.com/handsome-zyc/p/11722010.html