From 5719bbc16c5ecba4ec20a18e37d52b18370c0bcd Mon Sep 17 00:00:00 2001
From: Bruno Freitas Tissei <bft15@inf.ufpr.br>
Date: Thu, 6 Jun 2019 20:09:01 -0300
Subject: [PATCH] Add la4509
Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>
---
algorithms/graph/bellman_ford.cpp | 11 ++-
contests/Cadernaveis/LA4509.cpp | 110 ++++++++++++++++++++++++++++++
2 files changed, 119 insertions(+), 2 deletions(-)
create mode 100644 contests/Cadernaveis/LA4509.cpp
diff --git a/algorithms/graph/bellman_ford.cpp b/algorithms/graph/bellman_ford.cpp
index 301d3b2..cb5674f 100644
--- a/algorithms/graph/bellman_ford.cpp
+++ b/algorithms/graph/bellman_ford.cpp
@@ -2,6 +2,8 @@
///
/// Time: O(V * E)
/// Space: O(V + E)
+///
+/// Status: Tested (LA4509)
struct BellmanFord {
struct Edge { int u, v, w; };
@@ -11,12 +13,17 @@ struct BellmanFord {
vector<Edge> graph;
BellmanFord(int N) :
- N(N), dist(N) {}
+ N(N), dist(N)
+ { init(); }
void init() {
fill(all(dist), inf);
}
+ void add_edge(int u, int v, int w) {
+ graph.pb({ u, v, w });
+ }
+
int run(int s, int d) {
dist[s] = 0;
@@ -30,7 +37,7 @@ struct BellmanFord {
// there is one
for (auto e : graph)
if (dist[e.u] != inf &&
- dist[e.u] + w < dist[e.v])
+ dist[e.u] + e.w < dist[e.v])
return -inf;
return dist[d];
diff --git a/contests/Cadernaveis/LA4509.cpp b/contests/Cadernaveis/LA4509.cpp
new file mode 100644
index 0000000..7ee3f60
--- /dev/null
+++ b/contests/Cadernaveis/LA4509.cpp
@@ -0,0 +1,110 @@
+#include <bits/stdc++.h>
+
+#define MAX 40
+#define EPS 1e-6
+#define MOD 1000000007
+#define inf 0x3f3f3f3f
+#define llinf 0x3f3f3f3f3f3f3f3f
+
+#define fi first
+#define se second
+#define pb push_back
+#define ende '\n'
+
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define mset(x, y) memset(&x, (y), sizeof(x))
+
+using namespace std;
+
+using ll = long long;
+using ii = pair<int,int>;
+
+int dx[] = {-1, 1, 0, 0};
+int dy[] = {0, 0, 1, -1};
+
+int mat[MAX][MAX];
+
+struct BellmanFord {
+ struct Edge { int u, v, w; };
+
+ int N;
+ vector<int> dist;
+ vector<Edge> graph;
+
+ BellmanFord(int N) :
+ N(N), dist(N)
+ { init(); }
+
+ void init() {
+ fill(all(dist), inf);
+ }
+
+ void add_edge(int u, int v, int w) {
+ graph.pb({ u, v, w });
+ }
+
+ int run(int s, int d) {
+ dist[s] = 0;
+
+ for (int i = 0; i < N; ++i)
+ for (auto e : graph)
+ if (dist[e.u] != inf &&
+ dist[e.u] + e.w < dist[e.v])
+ dist[e.v] = dist[e.u] + e.w;
+
+ for (auto e : graph)
+ if (dist[e.u] != inf &&
+ dist[e.u] + e.w < dist[e.v])
+ return -inf;
+
+ return dist[d];
+ }
+};
+
+int main() {
+ ios::sync_with_stdio(0);
+ cin.tie(0);
+
+ int r, c;
+ while (cin >> c >> r && (c || r)) {
+ mset(mat, 0);
+ BellmanFord bell(r*c);
+
+ int g; cin >> g;
+ for (int i = 0; i < g; ++i) {
+ int x, y; cin >> x >> y;
+ mat[y][x] = 1;
+ }
+
+ int e; cin >> e;
+ for (int i = 0; i < e; ++i) {
+ int x1, y1; cin >> x1 >> y1;
+ int x2, y2; cin >> x2 >> y2;
+ int t; cin >> t;
+
+ bell.add_edge(y1 * c + x1, y2 * c + x2, t);
+ mat[y1][x1] = 1;
+ }
+
+ mat[r-1][c-1] = 1;
+ for (int i = 0; i < r; ++i)
+ for (int j = 0; j < c; ++j)
+ if (!mat[i][j])
+ for (int k = 0; k < 4; ++k) {
+ int di = i + dx[k];
+ int dj = j + dy[k];
+
+ if (di >= 0 && di < r && dj >= 0 && dj < c)
+ bell.add_edge(i*c + j, di*c + dj, 1);
+ }
+
+ int ans = bell.run(0, (r-1)*c + (c-1));
+
+ if (ans == -inf) cout << "Never" << ende;
+ else if (ans == inf) cout << "Impossible" << ende;
+ else cout << ans << ende;
+ }
+
+ return 0;
+}
--
GitLab