18 lines
357 B
C++
18 lines
357 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 200010;
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typedef long long LL;
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unordered_map<int, int> _map;
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int a[N];
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int n;
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int c;
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LL ans;
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int main() {
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cin >> n >> c;
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for (int i = 1; i <= n; i++)cin >> a[i], _map[a[i]]++;
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for (int i = 1; i <= n; i++)ans += _map[a[i] - c];
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cout << ans << endl;
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return 0;
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} |