Submission #969952

#	Time	Username	Problem	Language	Result	Execution time	Memory
969952		steveonalex	Robots (APIO13_robots)	C++17	100 / 100	485 ms	113748 KiB

robots

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
 
// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
 
ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b){a = b; return true;}
        return false;
    }
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b){a = b; return true;}
        return false;
    }
template <class T>
    void printArr(T& a, string separator = " ", string finish = "\n", ostream& out = cout){
        for(auto i: a) out << i << separator;
        out << finish;
    }
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
 
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
 
const int N = 505, K = 9, INF = 1e9 + 69;
 
enum GridObj{none=0, obstacle=1, anti_clockwise=2, clockwise=3};
 
int n, w, h;
int dp[K][K][N][N];
GridObj grid[N][N];

pair<short, short> graph[N][N][4];
int num[N][N][4];


void dfs(short i, short j, short x){
    array<short, 3> u = {{i, j, x}};

    if (num[u[0]][u[1]][u[2]] == 1) {
        graph[u[0]][u[1]][u[2]] = {-1, -1};
        return;
    }
    num[u[0]][u[1]][u[2]] = 1;
    
    array<short, 3> v = {{u[0] + dx[u[2]], u[1]+ dy[u[2]], u[2]}};
    if (grid[v[0]][v[1]] == anti_clockwise) v[2] = (v[2] + 1) % 4;
    else if (grid[v[0]][v[1]] == clockwise) v[2] = (v[2] + 3) % 4;

    if (grid[v[0]][v[1]] == obstacle){
        graph[u[0]][u[1]][u[2]] = {u[0], u[1]};
    }
    else {
        dfs(v[0], v[1], v[2]);
        graph[u[0]][u[1]][u[2]] = graph[v[0]][v[1]][v[2]];
    }
    num[u[0]][u[1]][u[2]] = 2;
}
 
 
pair<int, int> pos[K];

bool visited[N][N];
 
vector<pair<short, short>> q[N * N];
 
void dijkstra(int l, int r){
    memset(visited, 0, sizeof visited);
    int cnt = 0;
    if (l < r){
        for(int mid = l; mid < r; ++mid){
            for(int i = 1; i<=w; ++i) for(int j = 1;j <=h; ++j) 
                minimize(dp[l][r-l][i][j], dp[l][mid-l][i][j] + dp[mid+ 1][r-mid-1][i][j]);
        }
    }
    for(short i = 1; i<=w; ++i) for(short j = 1;j <=h; ++j) if (dp[l][r-l][i][j] < INF) {
        q[dp[l][r-l][i][j]].push_back({i, j});
        cnt++;
    }
 
    for(int distance = 0; cnt > 0; ++distance){
        while(q[distance].size()){
            pair<short, short> u = q[distance].back(); q[distance].pop_back();
            cnt--;
 
            // cout << distance << " "; printArr(u); cout.flush();
 
            if (visited[u.first][u.second]) continue;
            visited[u.first][u.second] = true;
            
            for(int x= 0; x < 4; ++x){
                pair<short, short> v = graph[u.first][u.second][x];
                if (v.first != -1) {
                    if (minimize(dp[l][r-l][v.first][v.second], distance + 1)) {
                        q[distance + 1].push_back(v);
                        cnt++;
                    }
                }
            }
        }
    }
 
    // for(int i = 1; i<=w; ++i) {
    //     for(int j = 1; j<=h; ++j) cout << dp[l][r-l][i][j] << " ";
    //     cout << "\n";
    // }
    // cout << "\n";
}

 
int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
    cin >> n >> w >> h;
    swap(w, h);
    if (n == 1){
        cout << 0 << "\n";
        return 0;
    }
    for(int i = 0; i<=w+1; ++i) 
    for(int j = 0; j<=h+1; ++j) grid[i][j] = obstacle;
    for(int i = 0; i<w; ++i){
        string s; cin >> s;
        for(int j = 0; j<h; ++j){
            if (s[j] == '.') grid[i+1][j+1]=none;
            else if (s[j] == 'x') grid[i+1][j+1] = obstacle;
            else if (s[j] == 'A') grid[i+1][j+1] = anti_clockwise;
            else if (s[j] == 'C') grid[i+1][j+1] = clockwise;
            else {
                grid[i+1][j+1]=none;
                pos[s[j] - '0' - 1] = {i + 1, j + 1};
            }
        }
    }

    for(int i = 1; i<=w; ++i) for(int j = 1; j<=h; ++j) if (grid[i][j] != obstacle){
        for(int x = 0; x < 4; ++x) if (!num[i][j][x]){
            dfs(i, j, x);
        }
    }
 
    memset(dp, 63, sizeof dp);
 
    for(int i = 0; i<n; ++i){
        dp[i][0][pos[i].first][pos[i].second] = 0;
    }
 
    for(int i = n-1; i>=0; --i)
    for(int j = i; j<n; ++j){
        dijkstra(i, j);
    }
    
    int ans = INF;
    for(int i = 1; i<=w; ++i) for(int j = 1; j<=w; ++j) 
        minimize(ans, dp[0][n-1][i][j]);
 
    if (ans == INF) ans = -1;
    cout << ans << "\n";
 
 
    return 0;
}

Compilation message (stderr)

robots.cpp: In function 'void dfs(short int, short int, short int)':
robots.cpp:70:32: warning: narrowing conversion of '(((int)u.std::array<short int, 3>::operator[](0)) + dx[((int)u.std::array<short int, 3>::operator[](2))])' from 'int' to 'short int' [-Wnarrowing]
   70 |     array<short, 3> v = {{u[0] + dx[u[2]], u[1]+ dy[u[2]], u[2]}};
robots.cpp:70:48: warning: narrowing conversion of '(((int)u.std::array<short int, 3>::operator[](1)) + dy[((int)u.std::array<short int, 3>::operator[](2))])' from 'int' to 'short int' [-Wnarrowing]
   70 |     array<short, 3> v = {{u[0] + dx[u[2]], u[1]+ dy[u[2]], u[2]}};

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 40 / 40