結果

問題 No.34 砂漠の行商人
コンテスト
ユーザー raven7959
提出日時 2022-08-22 16:48:40
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 24 ms / 5,000 ms
コード長 6,878 bytes
コンパイル時間 2,769 ms
コンパイル使用メモリ 228,160 KB
最終ジャッジ日時 2025-01-31 02:47:49
ジャッジサーバーID
（参考情報） 		judge3 / judge3
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ファイルパターン 結果
other AC * 26
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ソースコード

diff # 

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,fma,abm,mmx,avx,avx2")
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
#define yn(joken) cout<<((joken) ? "Yes" : "No")<<"\n"
#define YN(joken) cout<<((joken) ? "YES" : "NO")<<"\n"
using namespace std;
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<string>;
using vc = vector<char>;
using vd = vector<double>;
using vld = vector<long double>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;
using vvs = vector<vector<string>>;
using vvc = vector<vector<char>>;
using vvd = vector<vector<double>>;
using vvld = vector<vector<long double>>;
using vvvi = vector<vector<vector<int>>>;
using vvvl = vector<vector<vector<ll>>>;
using vvvvi = vector<vector<vector<vector<int>>>>;
using vvvvl = vector<vector<vector<vector<ll>>>>;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
const int INF = 1e9;
const ll LINF = 2e18;
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T& a, const T& b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}
bool ispow2(int i) { return i && (i & -i) == i; }
bool ispow2(ll i) { return i && (i & -i) == i; }
template <class T>
vector<T> make_vec(size_t a) {
    return vector<T>(a);
}
template <class T, class... Ts>
auto make_vec(size_t a, Ts... ts) {
    return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}
template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
    for (int i = 0; i < int(v.size()); i++) {
        is >> v[i];
    }
    return is;
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    for (int i = 0; i < int(v.size()); i++) {
        os << v[i];
        if (i < int(v.size()) - 1) os << ' ';
    }
    return os;
}

static uint32_t RandXor(){
    static uint32_t x=123456789;
    static uint32_t y=362436069;
    static uint32_t z=521288629;
    static uint32_t w=88675123;
    uint32_t t;
 
    t=x^(x<<11);
    x=y; y=z; z=w;
    return w=(w^(w>>19))^(t^(t>>8));
}

static double Rand01(){
    return (RandXor()+0.5)*(1.0/UINT_MAX);
}

template <typename T = int>
struct Edge{
    int from, to;
    T cost;
    int idx;
    Edge() = default;
    Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}
    operator int() const { return to; }
};

template <typename T = int>
struct Graph{
    vector<vector<Edge<T>>> g;
    int es;
    Graph() = default;
    explicit Graph(int n) : g(n), es(0) {}
    size_t size() const{
        return g.size();
    }

    void add_directed_edge(int from, int to, T cost = 1){
        g[from].emplace_back(from, to, cost, es++);
    }

    void add_edge(int from, int to, T cost = 1){
        g[from].emplace_back(from, to, cost, es);
        g[to].emplace_back(to, from, cost, es++);
    }

    void read(int M, int padding = -1, bool weighted = false, bool directed = false){
        for (int i = 0; i < M; i++){
            int a, b;
            cin >> a >> b;
            a += padding;
            b += padding;
            T c = T(1);
            if (weighted) cin >> c;
            if (directed) add_directed_edge(a, b, c);
            else add_edge(a, b, c);
        }
    }

    inline vector<Edge<T>> &operator[](const int &k){
        return g[k];
    }

    inline const vector<Edge<T>> &operator[](const int &k) const{
        return g[k];
    }
};

template <typename T = int>
using Edges = vector<Edge<T>>;

// dijkstra(g,start) とする. 返り値は以下の3つ.
// startからの最短距離の配列 dist
// 最短経路でその頂点の前に通る頂点の配列 from (startおよび到達不能頂点では-1)
// 最短経路でその頂点の前に通る辺の辺番号の配列 idx (startおよび到達不能頂点では-1)

template <typename T>
struct ShortestPath{
    vector<T> dist;
    vector<int> from, id;
};

template <typename T>
ShortestPath<T> dijkstra(const Graph<T> &g, int s){
    const auto INF = numeric_limits<T>::max();
    vector<T> dist(g.size(), INF);
    vector<int> from(g.size(), -1), id(g.size(), -1);
    using Pi = pair<T, int>;
    priority_queue<Pi, vector<Pi>, greater<>> que;
    dist[s] = 0;
    que.emplace(dist[s], s);
    while (!que.empty()){
        T cost;
        int idx;
        tie(cost, idx) = que.top();
        que.pop();
        if (dist[idx] < cost) continue;
        for (auto &e : g[idx]){
            auto next_cost = cost + e.cost;
            if (dist[e.to] <= next_cost) continue;
            dist[e.to] = next_cost;
            from[e.to] = idx;
            id[e.to] = e.idx;
            que.emplace(dist[e.to], e.to);
        }
    }
    return {dist, from, id};
}

void solve(){
    using T=tuple<int,int,int,int>;

    int N,V,sy,sx,gy,gx;
    cin>>N>>V>>sy>>sx>>gy>>gx;
    sx--; sy--; gx--; gy--;
    vvi F(N,vi(N));
    rep(i,N) cin>>F[i];
    vvi MD(N,vi(N,INF)),MV(N,vi(N,-1));
    vi dx={0,-1,0,1},dy={-1,0,1,0};
    auto inside=[&](int x,int y){
        return 0<=x && x<N && 0<=y && y<N;
    };
    Graph<int> G(N*N);
    rep(i,N){
        rep(j,N){
            rep(d,4){
                int nx=i+dx[d],ny=j+dy[d];
                if(!inside(nx,ny)) continue;
                G.add_directed_edge(i*N+j,nx*N+ny,F[nx][ny]);
            }
        }
    }
    auto ret=dijkstra(G,sx*N+sy).dist;
    if(ret[gx*N+gy]>=V){
        cout<<-1<<endl;
        return;
    }
    priority_queue<T,vector<T>,greater<T>> pq; // d,v,x,y
    pq.emplace(0,-V,sx,sy);
    MD[sx][sy]=0;
    MV[sx][sy]=V;
    while(sz(pq)){
        auto [d,v,x,y]=pq.top();
        pq.pop();
        v=-v;
        if(x==gx && y==gy){
            cout<<d<<endl;
            return;
        }
        if(d>MD[x][y] && v<MV[x][y]) continue;
        rep(i,4){
            int nx=x+dx[i],ny=y+dy[i];
            if(!inside(nx,ny)) continue;
            if(v-F[nx][ny]<=0) continue;
            if(d+1>MD[nx][ny]){
                if(v-F[nx][ny]<=MV[nx][ny]) continue;
                MD[nx][ny]=d+1;
                MV[nx][ny]=v-F[nx][ny];
                pq.emplace(d+1,-v+F[nx][ny],nx,ny);
            }
            else if(d+1==MD[nx][ny]){
                if(v-F[nx][ny]>MV[nx][ny]){
                    MV[nx][ny]=v-F[nx][ny];
                    pq.emplace(d+1,-v+F[nx][ny],nx,ny);
                }
            }
            if(d+1<MD[nx][ny]){
                MD[nx][ny]=d+1;
                MV[nx][ny]=v-F[nx][ny];
                pq.emplace(d+1,-v+F[nx][ny],nx,ny);
            }
        }
    }
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();
}
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