Submission #61398

#	Time	Username	Problem	Language	Result	Execution time	Memory
61398		kingpig9	Mountains (IOI17_mountains)	C++11	100 / 100	53 ms	15356 KiB

mountains

#include <bits/stdc++.h>
#include "mountains.h"

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 2018;

#define debug(...) fprintf(stderr, __VA_ARGS__)
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define fillchar(a, s) memset((a), (s), sizeof(a))

int N;
int dp[MAXN][MAXN], A[MAXN];

int maximum_deevs (vector<int> v) {
	N = v.size();
	copy(all(v), A);

	for (int rt = 0; rt < N; rt++) {
		dp[rt][rt] = 1;

		int block = rt;	//which one IS BLOCKING others?
		int notsee = 0;	//which one you guarantee not see?

		for (int lt = rt - 1; lt >= 0; lt--) {
			dp[lt][rt] = dp[lt][rt - 1];
			ll dx1 = block - lt, dy1 = A[block] - A[lt], dx2 = rt - lt, dy2 = A[rt] - A[lt];
			if (dx1 * dy2 >= dx2 * dy1) {
				if (lt + 1 <= block - 1) {
					notsee += dp[lt + 1][block - 1];
				}
				block = lt;
			}

			dp[lt][rt] = max(dp[lt][rt], notsee + 1 + (lt < block ? dp[lt][block - 1] : 0));
		}
	}
	return dp[0][N - 1];
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30