[20251204] BOJ / P3 / Mowing the Lawn / 권혁준

Author: oncsr

khj20006/202512/04 BOJ P3 Mowing the Lawn.md

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+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+int N, K;
+ll dp[100001]{}, s[100001]{};
+deque<pair<ll, int>> d;
+
+int main() {
+	cin.tie(0)->sync_with_stdio(0);
+
+	cin >> N >> K;
+	for (int i = 1, a; i <= N; i++) {
+		cin >> a;
+		s[i] = s[i - 1] + a;
+	}
+
+	ll ans = 0;
+	d.emplace_back(s[N], -1);
+	d.emplace_back(s[N] - s[1], 0);
+	for (int i = 1; i <= N; i++) {
+		while (!d.empty() && i - d.front().second > K + 1) d.pop_front();
+		int idx = d.front().second;
+		dp[i] = (idx >= 0 ? dp[idx] : 0) + s[i] - s[idx + 1];
+
+		ans = max(ans, dp[i]);
+		if (i < N) {
+			ll val = dp[i] + s[N] - s[i + 1];
+			while (!d.empty() && d.back().first <= val) d.pop_back();
+			d.emplace_back(val, i);
+		}
+	}
+	cout << ans;
+
+}
+```