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Submission #127581

# Submission time Handle Problem Language Result Execution time Memory
127581 2019-07-09T15:29:41 Z Vlatko Maja (COCI18_maja) C++14
110 / 110
 883 ms 632 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const ll inf = 1e18;
const int maxn = 100;

int di[4] = {-1, 0, 1, 0};
int dj[4] = {0, 1, 0, -1};

int N, M, A, B;
ll K, T;
array<array<ll, maxn>, maxn> C, cur, nxt;
// dp[k][i][j] = max sum for path to here after k steps

template<class T>
inline void max_self(T& a, T& b) {
	a = max(a, b);
}

void dp_step() {
	for (int i = 0; i < N; ++i) {
		for (int j = 0; j < M; ++j) {
			nxt[i][j] = -inf;
			if (i > 0)   max_self(nxt[i][j], cur[i-1][j]);
			if (i+1 < N) max_self(nxt[i][j], cur[i+1][j]);
			if (j > 0)   max_self(nxt[i][j], cur[i][j-1]);
			if (j+1 < M) max_self(nxt[i][j], cur[i][j+1]);
			if (nxt[i][j] != -inf) nxt[i][j] += C[i][j];
		}
	}
	swap(cur, nxt);
}

void simulate() {
	for (int i = 0; i < N; ++i) {
		for (int j = 0; j < M; ++j) {
			ll gains = 0;
			if (i > 0)   max_self(gains, C[i-1][j]);
			if (i+1 < N) max_self(gains, C[i+1][j]);
			if (j > 0)   max_self(gains, C[i][j-1]);
			if (j+1 < M) max_self(gains, C[i][j+1]);
			gains += C[i][j];
			cur[i][j] += gains * (K - 2*T) / 2;
		}
	}
}

int main() {
	ios::sync_with_stdio(false); cin.tie(0);
	cin >> N >> M >> A >> B >> K;
	--A, --B;
	T = N * M * 2;
	for (int i = 0; i < N; ++i) {
		for (int j = 0; j < M; ++j) {
			cin >> C[i][j];
			cur[i][j] = -inf;
		}
	}
	cur[A][B] = 0;
	if (2*T >= K) {
		for (int i = 0; i < K; ++i) {
			dp_step();
		}
	} else {
		// T steps, simulate going back and forth, T steps again
		for (int i = 0; i < T; ++i) {
			dp_step();
		}
		simulate();
		for (int i = 0; i < T; ++i) {
			dp_step();
		}
	}
	cout << cur[A][B] << '\n';
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 504 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 504 KB Output is correct
2 Correct 6 ms 508 KB Output is correct

Subtask #3
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 508 KB Output is correct
2 Correct 12 ms 504 KB Output is correct

Subtask #4
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 504 KB Output is correct
2 Correct 5 ms 504 KB Output is correct

Subtask #5
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 147 ms 504 KB Output is correct
2 Correct 9 ms 504 KB Output is correct
3 Correct 464 ms 632 KB Output is correct

Subtask #6
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 504 KB Output is correct
2 Correct 695 ms 632 KB Output is correct
3 Correct 472 ms 632 KB Output is correct

Subtask #7
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 551 ms 612 KB Output is correct
2 Correct 883 ms 632 KB Output is correct

Subtask #8
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 118 ms 568 KB Output is correct
2 Correct 111 ms 596 KB Output is correct

Subtask #9
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 35 ms 548 KB Output is correct
2 Correct 19 ms 504 KB Output is correct

Subtask #10
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 592 KB Output is correct
2 Correct 16 ms 504 KB Output is correct