Submission #509958

#	Time	Username	Problem	Language	Result	Execution time	Memory
509958		blue	Robots (APIO13_robots)	C++17	60 / 100	216 ms	163844 KiB

robots

#include <iostream>
#include <algorithm>
#include <set>
#include <queue>
#include <vector>
using namespace std;

using vi = vector<int>;
using ll = long long;
using vll = vector<ll>;
using pii = pair<int, int>;
using vvi = vector<vi>;

const int fr = 0;
const int lt = 3;
const int rt = 1;
const int bl = 2;

int n, h, w;

int mov[5];

// const int tm

vvi edge;
vvi rev_edge;

void add_edge(int u, int v)
{
    edge[u].push_back(v);
    rev_edge[v].push_back(u);
}





const int INF = 10'000'000;

vi occ[500*500*9];
vi* act_edge;

void bfs(vi& dst, int mxd)
{
    // cerr <<"bfs called\n";
    // bool flg = (mxd==0);
    queue<int> tbv;
    for(int d = 0; d <= mxd; d++)
    {
        // cerr << "d = " << d << ", mxd = " << mxd << '\n';
        for(int o: occ[d])
        {
            // cerr << "o = " << o << '\n';
            if(dst[o] != d) continue;
            tbv.push(o);
        }
        // cerr << "chk\n";

        while((!tbv.empty()) && dst[tbv.front()] == d)
        {
            int u = tbv.front();
            tbv.pop();

            for(int v: act_edge[u])
            {
                if(dst[v] <= dst[u] + 1) continue;
                dst[v] = dst[u] + 1;
                tbv.push(v);
                mxd = max(mxd, dst[v]);
            }
        }
    }
}









int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> w >> h;

    vi state((h+2)*(w+2), bl);

    int loc[n];

    for(int r = 1; r <= h; r++)
    {
        for(int c = 1; c <= w; c++)
        {
            int i = (w+2)*r+c;

            char z;
            cin >> z;

            if('1' <= z && z <= '9')
            {
                loc[z-'1'] = i;
                state[i] = fr;
            }
            else if(z == '.')
            {
                state[i] = fr;
            }
            else if(z == 'A')
            {
                state[i] = lt;
            }
            else if(z == 'C')
            {
                state[i] = rt;
            }
            else if(z == 'x')
            {
                state[i] = bl;
            }
        }
    }

    mov[0] = -(w+2); //0 = top
    mov[1] = +1; //1 = right
    mov[2] = +(w+2); //2 = down
    mov[3] = -1; //3 = left
    mov[4] = 0;

    // vi edge[5*(h+2)*(w+2)];
    // vi in_edgd
    edge = vvi(5*(h+2)*(w+2));
    rev_edge = vvi(5*(h+2)*(w+2));

    vi dest(5*(h+2)*(w+2), -1);
    queue<int> tbv;

    for(int r = 1; r <= h; r++)
    {
        for(int c = 1; c <= w; c++)
        {
            int i = (w+2)*r + c;

            if(state[i] == bl) continue;

            // cerr << r << ' ' << c << '\n';

            for(int dir = 0; dir <= 3; dir++)
            {
                // cerr << "   " << dir << '\n';
                add_edge(5*i + 4, 5*i + dir);
                // cerr << "A\n";
                if(state[i + mov[dir]] != bl)
                {
                    // cerr << "B\n";
                    add_edge(5*i + dir, 5*(i + mov[dir]) + (dir + state[i + mov[dir]])%4);
                    // cerr << "C\n";
                }
                else
                {
                    // cerr << "D\n";
                    add_edge(5*i + dir, 5*i + 4);
                    dest[5*i + dir] = i;
                    tbv.push(5*i + dir);
                    // cerr << "E\n";
                }
            }
        }
    }
    // cerr << "A\n";



    while(!tbv.empty())
    {
        int u = tbv.front();
        tbv.pop();
        for(int v: rev_edge[u])
        {
            if(v % 5 == 4) continue;
            if(dest[v] != -1) continue;
            dest[v] = dest[u];
            tbv.push(v);
        }
    }


    act_edge = new vi[(h+2)*(w+2)];
    for(int r = 1; r <= h; r++)
    {
        for(int c = 1; c <= w; c++)
        {
            int ind = (w+2)*r + c;

            for(int q = 0; q < 4; q++)
            {
                if(dest[5*ind + q] ==  -1 || dest[5*ind+q] == ind) continue;
                act_edge[ind].push_back(dest[5*ind+q]);
            }

            // cerr << "current cell = " << r << ' ' << c << " : ";
            // for(int a: act_edge[ind]) cerr << a/(w+2) << " " << a%(w+2) << " | ";
            // cerr << '\n';
        }
    }

    // for(int f = )
    edge.clear();
    rev_edge.clear();
    dest.clear();
    state.clear();

















    vi dp[n][n];
    for(int i = 0; i < n; i++)
    {
        occ[0].push_back(loc[i]);
        dp[i][i] = vi((h+2)*(w+2), INF);
        dp[i][i][loc[i]] = 0;
        bfs(dp[i][i], 0);
        occ[0].pop_back();

        // cerr << "\n\n\n";
        // cerr << "robot = " << i+1 << '\n';
        // for(int l = 0; l < (h+2)*(w+2); l++)
        // {
        //     if(dp[i][i][l] >= INF) continue;
        //     // cerr << l/(w+2) << ' ' << l%(w+2) << " : " << dp[i][i][l] << '\n';
        // }
    }

    for(int d = 1; d < n; d++)
    {
        for(int i = 0; i+d < n; i++)
        {
            int j = i+d;
            // cerr << "\n\n\n computing dp " << i << ' ' << j << '\n';

            dp[i][j] = vi((h+2)*(w+2), INF);

            for(int k = i; k < j; k++)
            {
                for(int x = 0; x < (h+2)*(w+2); x++)
                {
                    dp[i][j][x] = min(dp[i][j][x], dp[i][k][x] + dp[k+1][j][x]);
                }
            }

            vi elim;

            for(int u = 0; u < (h+2)*(w+2); u++)
                if(dp[i][j][u] < INF) //add constraint on bfs here?
                {
                    occ[dp[i][j][u]].push_back(u);
                    elim.push_back(dp[i][j][u]);
                }

            bfs(dp[i][j], d*h*w);

            for(int e: elim) occ[e].clear();
        }
    }

    int final_ans = INF;

    for(int u = 0; u < (h+2)*(w+2); u++)
    {
        final_ans = min(final_ans, dp[0][n-1][u]);
    }

    if(final_ans >= INF) final_ans = -1;
    cout << final_ans << '\n';
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 0 / 40