結果
問題 | No.20 砂漠のオアシス |
ユーザー | sak |
提出日時 | 2020-06-07 11:51:37 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 35 ms / 5,000 ms |
コード長 | 2,923 bytes |
コンパイル時間 | 2,559 ms |
コンパイル使用メモリ | 216,324 KB |
最終ジャッジ日時 | 2025-01-10 23:43:22 |
ジャッジサーバーID (参考情報) |
judge4 / judge1 |
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ファイルパターン | 結果 |
---|---|
other | AC * 21 |
ソースコード
#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<ll, ll> p_ll; template<class T> void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; } #define repr(i,from,to) for (int i=(int)from; i<(int)to; i++) #define all(vec) vec.begin(), vec.end() #define rep(i,N) repr(i,0,N) #define per(i,N) for (int i=(int)N-1; i>=0; i--) const ll MOD = pow(10,9)+7; const ll LLINF = pow(2,61)-1; const int INF = pow(2,30)-1; vector<ll> fac; void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; } ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; } ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; } ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); } ll lcm(ll a, ll b) { return a/gcd(a,b)*b; } // ---------------------------------------------------------------------- // ---------------------------------------------------------------------- struct edge { p_ll to; ll d; }; vector<vector<vector<edge>>> adj; vector<vector<ll>> dijkstra(int n=0, int m=0) { int N = adj.size(), M = adj[0].size(); auto c = [](const pair<p_ll, ll> &x, const pair<p_ll, ll> &y){return x.second>y.second;}; priority_queue<pair<p_ll, ll>, vector<pair<p_ll, ll>>, decltype(c)> q(c); vector<vector<ll>> result(N,vector<ll>(M,LLINF)); result[n][m] = 0; q.push(make_pair(make_pair(n,m),0)); while(q.size()) { pair<p_ll, ll> now = q.top(); q.pop(); p_ll np = now.first; ll np1 = np.first, np2 = np.second; ll nd = now.second; if (nd>result[np1][np2]) continue; for (auto x: adj[np1][np2]) { ll xt1 = x.to.first, xt2 = x.to.second; if (result[xt1][xt2]<=result[np1][np2]+x.d) continue; q.push(make_pair(make_pair(xt1, xt2), result[np1][np2]+x.d)); result[xt1][xt2] = result[np1][np2]+x.d; } } return result; } // ---------------------------------------------------------------------- // ---------------------------------------------------------------------- int main() { ll N, V, ox, oy; cin >> N >> V >> oy >> ox; ox--; oy--; ll L[N][N]; rep(i,N) rep(j,N) cin >> L[i][j]; adj.resize(N); rep(i,N) adj[i].resize(N); rep(i,N) rep(j,N) { if (i!=0 ) adj[i][j].push_back({make_pair(i-1,j), L[i-1][j]}); if (i!=N-1) adj[i][j].push_back({make_pair(i+1,j), L[i+1][j]}); if (j!=0 ) adj[i][j].push_back({make_pair(i,j-1), L[i][j-1]}); if (j!=N-1) adj[i][j].push_back({make_pair(i,j+1), L[i][j+1]}); } vector<vector<ll>> sd = dijkstra(0,0); // rep(i,N) debug(all(sd[i])); string result = "NO"; if (ox==-1&&oy==-1) { if (sd[N-1][N-1]<V) result = "YES"; } else { vector<vector<ll>> od = dijkstra(ox,oy); if ((V-sd[ox][oy])*2-od[N-1][N-1]>0) result = "YES"; } cout << result << endl; return 0; }