题解

#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, x;
    cin >> n >> x;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    int ans = 0;
    // 枚举所有长度为4的窗口：起点i从0到n-4
    for (int i = 0; i <= n - 4; ++i) {
        int max_val = INT_MIN;
        int min_val = INT_MAX;
        // 遍历窗口内4个元素
        for (int j = i; j < i + 4; ++j) {
            max_val = max(max_val, a[j]);
            min_val = min(min_val, a[j]);
        }
        if (max_val - min_val < x) {
            ans++;
        }
    }

    cout << ans << endl;
    return 0;
}