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https://git.sb/baoshuo/OI-codes.git
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97 lines
1.6 KiB
C++
97 lines
1.6 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <cmath>
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#include <functional>
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#include <queue>
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#include <utility>
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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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const int N = 1e5 + 5;
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int n, k, p = 1, a[N], pre[N], nxt[N], ans;
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bool vis[N];
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std::priority_queue<std::pair<int, int>> q;
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std::vector<int> nums;
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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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cin >> n >> k;
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for (int i = 1, x; i <= n; i++) {
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cin >> x;
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if (static_cast<long long>(a[p]) * x < 0) {
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a[++p] = x;
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} else {
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a[p] += x;
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}
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nums.emplace_back(x);
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}
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std::sort(nums.begin(), nums.end(), std::greater<>());
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if (nums[0] < 0) {
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for (int i = 0; i < k; i++) {
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ans += nums[i];
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}
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cout << ans << endl;
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exit(0);
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}
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if (a[1] > 0 && a[p] > 0) {
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a[1] += a[p--];
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}
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int cnt = 0;
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for (int i = 1; i <= p; i++) {
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pre[i] = i == 1 ? p : i - 1;
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nxt[i] = i == p ? 1 : i + 1;
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if (a[i] > 0) {
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ans += a[i];
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cnt++;
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a[i] = -a[i];
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}
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q.emplace(a[i], i);
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}
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while (cnt > k) {
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int i = q.top().second;
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q.pop();
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if (vis[i]) continue;
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cnt--;
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ans += a[i];
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int l = pre[i],
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r = nxt[i];
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a[i] = a[l] + a[r] - a[i];
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pre[i] = pre[l];
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nxt[pre[l]] = i;
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vis[l] = true;
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pre[nxt[r]] = i;
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nxt[i] = nxt[r];
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vis[r] = true;
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q.emplace(a[i], i);
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}
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cout << ans << endl;
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return 0;
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}
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