hdu 3530

单调队列

两个

一个维护单增序列

另一个维护单降序列

#include <bits/stdc++.h>

const int N = 1e5 + 10;

int n, m, k, Ans;

struct Node {
    int id, val;
} Q_max[N], Q_min[N];
int head_max, head_min, from, tail_max, tail_min;

int main() {
    while(~ scanf("%d %d %d", &n, &m, &k)) {
        head_max = head_min = from = 1, tail_max = tail_min = Ans = 0;
        Node tmp;
        
        for(int i = 1; i <= n; i ++) {
            scanf("%d", &tmp.val);
            tmp.id = i;
            while(head_max <= tail_max && tmp.val >= Q_max[tail_max].val) tail_max --;
            Q_max[++ tail_max] = tmp;
            while(head_min <= tail_min && tmp.val <= Q_min[tail_min].val) tail_min --;
            Q_min[++ tail_min] = tmp;
            while(Q_max[head_max].val - Q_min[head_min].val > k) {
                if(Q_max[head_max].id < Q_min[head_min].id) {
                    from = Q_max[head_max].id + 1;
                    head_max ++;
                } else {
                    from = Q_min[head_min].id + 1;
                    head_min ++;
                }
            }
            if(Q_max[head_max].val - Q_min[head_min].val <= k && Q_max[head_max].val - Q_min[head_min].val >= m) {
                Ans = std:: max(Ans, i - from + 1);
            }
        }
        printf("%d\n", Ans);
    }