Submission #9903159

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Source Code Expand

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

int main() {
    int n, k; cin >> n >> k;
    vector<int> a(n);
    for (auto &ai: a) cin >> ai;
    long long cnt = 0;
    for (int mid = 0; mid < n; mid++) {
        int left = lower_bound(begin(a), end(a), a[mid] - k) - begin(a);
        int right = upper_bound(begin(a), end(a), a[mid] + k) - begin(a) - 1;
        cnt += 1LL * (right - mid) * (mid - left);
        cnt -= 1LL * (right - mid) * ((right - mid) - 1) / 2;   // bad
    }
    cout << cnt << endl;
    return 0;
}

Submission Info

Judge Result