結果
問題 | No.20 砂漠のオアシス |
ユーザー | koba-e964 |
提出日時 | 2016-12-26 14:17:05 |
言語 | C++11 (gcc 13.3.0) |
結果 |
AC
|
実行時間 | 52 ms / 5,000 ms |
コード長 | 2,877 bytes |
コンパイル時間 | 802 ms |
コンパイル使用メモリ | 99,492 KB |
実行使用メモリ | 6,820 KB |
最終ジャッジ日時 | 2024-10-13 05:45:13 |
合計ジャッジ時間 | 1,745 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge2 |
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ファイルパターン | 結果 |
---|---|
other | AC * 21 |
ソースコード
#include <algorithm>#include <bitset>#include <cassert>#include <cctype>#include <cmath>#include <cstdio>#include <cstdlib>#include <cstring>#include <ctime>#include <deque>#include <functional>#include <iomanip>#include <iostream>#include <list>#include <map>#include <numeric>#include <queue>#include <set>#include <sstream>#include <stack>#include <string>#include <utility>#include <vector>#define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++)/*** Dijkstra's algorithm.* First, call add_edge() to add edges.* Second, call solve() to calculate the length of the shortest path from source to each vertex.* Header requirement: algorithm, queue, vector* Verified by AtCoder ARC026-C (http://arc026.contest.atcoder.jp/submissions/604231)*/template<class Len = int>class Dijkstra {private:int n;std::vector<std::vector<std::pair<int, Len> > > edges;public:/*** n: the number of vertices*/Dijkstra(int n) : n(n), edges(n) {}/** from: the source of edge to add* to: the target of edge to add* cost: the cost of edge to add*/void add_edge(int from, int to, Len cost) {edges[from].push_back(std::pair<int, Len>(to, cost));}/** This function returns an array consisting of the distances from vertex source.*/std::vector<Len> solve(int source) {const Len inf = 1e8;typedef std::pair<Len, int> pi;std::vector<Len> d(n, inf);std::priority_queue<pi, std::vector<pi>, std::greater<pi> > que;que.push(pi(0, source));while (!que.empty()) {pi p = que.top(); que.pop();int idx = p.second;if (d[idx] <= p.first) {continue;}d[idx] = p.first;for(int j = 0; j < edges[idx].size(); ++j) {que.push(pi(p.first + edges[idx][j].second, edges[idx][j].first));}}return d;}};using namespace std;typedef long long int ll;typedef vector<int> VI;typedef vector<ll> VL;typedef pair<int, int> PI;int main(void){int n, v, ox, oy;cin >> n >> v >> ox >> oy;vector<VI> l(n, VI(n));REP(i, 0, n) {REP(j, 0, n) {cin >> l[i][j];}}// Constructs a graphDijkstra<int> dijk(n * n);REP(i, 0, n) {REP(j, 0, n) {int dx[4] = {1, 0, -1, 0};int dy[4] = {0, 1, 0, -1};REP(d, 0, 4) {int tx = i + dx[d];int ty = j + dy[d];if (0 > tx || tx >= n || 0 > ty || ty >= n) {continue;}dijk.add_edge(tx * n + ty, i * n + j, l[i][j]);}}}VI sol = dijk.solve(0);bool reachable = false;if (sol[n * n - 1] < v) {reachable = true;}if (not reachable && ox >= 1) {ox--, oy--;int to_oasis = sol[oy * n + ox];if (to_oasis < v) {int rem = 2 * (v - to_oasis);VI sol2 = dijk.solve(oy * n + ox);reachable = sol2[n * n - 1] < rem;}}cout << (reachable ? "YES": "NO") << endl;}