Submission #969610

#	Time	Username	Problem	Language	Result	Execution time	Memory
969610		rahidilbayramli	Mecho (IOI09_mecho)	C++17	100 / 100	140 ms	12684 KiB

mecho

#pragma GCC optimize("-O3")
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define pb push_back
#define p_b pop_back
#define f first
#define s second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const ll sz = 850;
char grid[sz][sz];
ll dist[sz][sz], ch[sz][sz], n, s, i, j, k;
ll dx[] = {0, 1, 0, -1};
ll dy[] = {1, 0, -1, 0};
pll st, en;
ll bfs(ll mid)
{
    if(dist[st.f][st.s] - mid * s <= 0)
        return 0;
    for(i = 1; i <= n; i++)
    {
        for(j = 1; j <= n; j++)
            ch[i][j] = 0;
    }
    queue<pll>q;
    q.push(st);
    while(!q.empty())
    {
        pll node = q.front();
        q.pop();
        for(k = 0; k < 4; k++)
        {
            pll nnode = {node.f + dx[k], node.s + dy[k]};
            if(nnode.f >= 1 && nnode.f <= n && nnode.s >= 1 && nnode.s <= n)
            {
                if(ch[nnode.f][nnode.s] == 0 && grid[nnode.f][nnode.s] != 'T' && grid[nnode.f][nnode.s] != 'M' && dist[nnode.f][nnode.s] - mid * s > ch[node.f][node.s] + 1)
                {
                    ch[nnode.f][nnode.s] = ch[node.f][node.s] + 1;
                    q.push(nnode);
                }
            }
        }
    }
    if(ch[en.f][en.s] > 0)
        return 1;
    return 0;
}
void solve()
{
    cin >> n >> s;
    queue<pll>q;
    for(i = 1; i <= n; i++)
    {
        for(j = 1; j <= n; j++){
            cin >> grid[i][j];
            if(grid[i][j] == 'M')
                st = {i, j};
            else    if(grid[i][j] == 'D')
                en = {i, j};
            else    if(grid[i][j] == 'H')
                q.push({i, j});
        }
    }
    while(!q.empty())
    {
        pll node = q.front();
        q.pop();
        for(k = 0; k < 4; k++)
        {
            pll nnode = {node.f + dx[k], node.s + dy[k]};
            if(nnode.f >= 1 && nnode.f <= n && nnode.s >= 1 && nnode.s <= n)
            {
                if(dist[nnode.f][nnode.s] == 0 && grid[nnode.f][nnode.s] != 'H' && grid[nnode.f][nnode.s] != 'T' && grid[nnode.f][nnode.s] != 'D')
                {
                    dist[nnode.f][nnode.s] = dist[node.f][node.s] + s;
                    q.push(nnode);
                }
            }
        }
    }
    dist[en.f][en.s] = LLONG_MAX;
    ll l = 0, r = 1000000000, ans = -1;
    while(l <= r)
    {
        ll mid = (l + r) / 2;
        if(bfs(mid))
        {
            ans = max(ans, mid);
            l = mid + 1;
        }
        else
            r = mid - 1;
    }
    cout << ans << "\n";
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    ll tests = 1;
    //cin >> tests;
    while(tests--)
    {
        solve();
    }
}

• Subtask 1: 100 / 100