Submission #417831

#	Time	Username	Problem	Language	Result	Execution time	Memory
417831		Kevin_Zhang_TW	The short shank; Redemption (BOI21_prison)	C++17	15 / 100	2075 ms	10904 KiB

prison

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

const int MAX_N = 4005, inf = 1e9;

int dp[MAX_N][MAX_N], n, D, T;

//           i can activate [i, nxt[i])
int s[MAX_N], nxt[MAX_N];

void solve_dp() {
	vector<int> ok(n + 10);
	for (int i = n;i >= 1;--i) {
		for (int j = i;j < nxt[i];++j)
			ok[j] = true;

		dp[i][1] = accumulate(begin(ok)+i, end(ok), 0);
		for (int j = 2;j <= n;++j) {
			dp[i][j] = inf;
			int sum = 0;
			for (int k = i+1;k <= n;++k) {
				sum += ok[k-1];
				chmin(dp[i][j], sum + dp[k][j-1]);
			}
		}
	}
}

int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> n >> D >> T;
	// Just to be faster
	assert(n < MAX_N);

	for (int i = 1;i <= n;++i) {
		cin >> s[i];
		nxt[i] = min(n+1, max(i, i + T - s[i] + 1));
	}

	solve_dp();

	cout << dp[1][D+1] << '\n';
}

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 0 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20