洛谷 P2032 扫描

洛谷 P2032 扫描

思路

单调队列例题，有多倍经验哦~~

多倍经验传送门:

P1886 滑动窗口

P1440 求m区间内的最小值

代码

//知识点:单调队列 
/*
By:Loceaner
*/
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;

inline int read() {
	char c = getchar();
	int x = 0, f = 1;
	for( ; !isdigit(c); c = getchar()) if(c == '-') f = -1;
	for( ; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ 48);
	return x * f;
}

const int N = 2e6 + 11;

int n, k, q[N], a[N];

void getmax() {
	int head = 0, tail = 0;
	for(int i = 1; i < k; i++) {
		while(head <= tail && a[q[tail]] <= a[i]) tail--;
		q[++tail] = i;
	}
	for(int i = k; i <= n; i++) {
		while(head <= tail && a[q[tail]] <= a[i]) tail--;
		q[++tail] = i;
		while(q[head] <= i - k) head++;
		cout << a[q[head]] << '
';
	}
}

int main() {
 	n = read(), k = read();
 	for(int i = 1; i <= n; i++) a[i] = read();
 	getmax();
	return 0;
}