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https://git.sb/baoshuo/OI-codes.git
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73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
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#include <iostream>
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#include <algorithm>
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#include <set>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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int n, a, b, c, d_up = 0, d_down = 0;
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long long ans = 0;
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cin >> n >> a >> b;
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std::vector<int> nums, x(n);
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for (int& x : x) {
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cin >> x;
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}
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std::set<int> s1;
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std::multiset<int> s2;
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for (int i = 0; i < n; i++) {
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s1.insert(x[i]);
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s2.insert(x[i]);
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if (i == 0) {
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c = x[i];
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} else { // i > 0
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if (c > x[i]) {
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ans += static_cast<long long>(a) * (c - x[i]);
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d_down++;
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} else if (c < x[i]) {
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ans += static_cast<long long>(b) * (x[i] - c);
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d_up++;
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}
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if (c != *s1.begin()) {
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auto it = --s1.lower_bound(c);
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int d = (d_up + s2.count(c)) * b - d_down * a;
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if (d < 0 && c != *it) {
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ans += static_cast<long long>(d) * (c - *it);
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d_up += s2.count(c);
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d_down -= s2.count(*it);
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c = *it;
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}
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}
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if (c != *s1.rbegin()) {
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auto it = s1.upper_bound(c);
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int d = (d_down + s2.count(c)) * a - d_up * b;
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if (d < 0 && c != *it) {
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ans += static_cast<long long>(d) * (*it - c);
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d_up -= s2.count(*it);
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d_down += s2.count(c);
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c = *it;
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}
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}
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}
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cout << ans << endl;
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}
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return 0;
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}
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