Submission #781004

#	Time	Username	Problem	Language	Result	Execution time	Memory
781004		canadavid1	Mecho (IOI09_mecho)	C++14	100 / 100	244 ms	6784 KiB

mecho

#include <bits/stdc++.h>

using namespace std;

struct Node
{
    bool g=true;
    int beesat=INT_MAX;
};
int N,S;
complex<int> start;
complex<int> end;
vector<vector<Node>> cell;

bool outOfRange(complex<int> a)
{
    return a.real() < 0 || a.real() >= N || a.imag() < 0 || a.imag() >= N;
}

template<typename T>
T& at(vector<vector<T>>& v,complex<int> p)
{
    return v[p.real()][p.imag()];
}

bool bfs(int m)
{
    queue<pair<complex<int>,int>> q;
    vector<vector<char>> seen(N,vector<char>(N,false));
    q.push({start,S*m});
    while(q.size())
    {
        auto a = q.front(); q.pop();
        if(at(seen,a.first)) continue;
        at(seen,a.first)=true;
        if(at(cell,a.first).beesat <= a.second) continue;
        if(a.first==::end) return true;
        for(auto i : initializer_list<complex<int>>{{1,0},{-1,0},{0,1},{0,-1}})
        {
            if(outOfRange(a.first+i)) continue;
            if(a.first+i!=::end&&!at(cell,a.first+i).g) continue;
            q.push({a.first+i,a.second+1});
        }
    }
    return false;
}


int main()
{
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> N >> S;
    cell.assign(N,vector<Node>(N));
    queue<complex<int>> bees;
    for(int i = 0; i < N; i++)
    {
        for(int j = 0; j < N; j++)
        {
            char a;
            cin >> a;
            switch(a)
            {
            case 'D':
                ::end = {i,j};
            case 'T':
                cell[i][j].g = false;
                break;
            case 'M':
                start = {i,j};
                break;
            case 'H':
                cell[i][j].beesat = 0;
                bees.push({i,j});
            case 'G':
                ;
            }
        }
    }
    while(bees.size())
    {
        auto a = bees.front();bees.pop();
        for(complex<int> i : initializer_list<complex<int>>{{1,0},{-1,0},{0,1},{0,-1}})
        {
            auto b = a+i;
            if(outOfRange(b)) continue;
            if (!at(cell,b).g || at(cell,b).beesat < INT_MAX) continue;
            at(cell,b).beesat = at(cell,a).beesat+S;
            bees.push(b);
        }
    }
    int l = -1;
    int r = N*N;
    while(l < r-1)
    {
        int m = (l+r)/2;
        if (bfs(m))
            l = m;
        else
            r = m;
    }
    cout << l << "\n";
}

• Subtask 1: 100 / 100