Submission #1318706

#	Time	Username	Problem	Language	Result	Execution time	Memory
1318706		mibngor	Tracks in the Snow (BOI13_tracks)	C++20	70.94 / 100	851 ms	355740 KiB

tracks

#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define pp pop_back
#define emp emplace_back
#define ins insert
#define fi first
#define se second
#define sz(x) x.size()
#define fop if(fopen("hello.inp","r")){freopen("hello.inp","r",stdin);freopen("hello.out","w",stdout);}
#define ls ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
ll Rd(ll l,ll r)
{
    return uniform_int_distribution<int>(l,r)(rd);
}
const int N = 4e3 + 7;
int h,w,x[4] = {0,1,0,-1},y[4] = {1,0,-1,0},rs = -1,dist[N][N];
bool vst[N][N];
char a[N][N];
void bfs(ll nx,ll ny)
{
    deque<pair<int,int>> dq;
    dq.push_back({nx,ny});
    dist[nx][ny] = 1;
    while(!dq.empty())
    {
        auto u = dq.front();
        dq.pop_front();
        if(vst[u.fi][u.se])
            continue;
        vst[u.fi][u.se] = 1;
        rs = max(rs,dist[u.fi][u.se]);
        for(int i = 0; i < 4; i++)
        {
            pair<int,int> v;
            v.fi = u.fi + x[i];
            v.se = u.se + y[i];
            if(v.fi < 1 || v.fi > h)
                continue;
            if(v.se < 1 || v.se > h)
                continue;
            if(a[v.fi][v.se] == '.')
                continue;
            if(a[v.fi][v.se] != a[u.fi][u.se])
            {
                dq.push_back(v);
                dist[v.fi][v.se] = dist[u.fi][u.se] + 1;
            }
            else
            {
                dq.push_front(v);
                dist[v.fi][v.se] = dist[u.fi][u.se];
            }
        }
    }
}
main()
{
    fop;
    ls;
    cin >> h >> w;
    for(int i = 1; i <= h; i++)
        for(int j = 1; j <= w; j++)
            cin >> a[i][j];
    bfs(1,1);
    cout << rs;
}

Compilation message (stderr)

tracks.cpp:59:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   59 | main()
      | ^~~~
tracks.cpp: In function 'int main()':
tracks.cpp:10:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 | #define fop if(fopen("hello.inp","r")){freopen("hello.inp","r",stdin);freopen("hello.out","w",stdout);}
      |                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:61:5: note: in expansion of macro 'fop'
   61 |     fop;
      |     ^~~
tracks.cpp:10:78: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 | #define fop if(fopen("hello.inp","r")){freopen("hello.inp","r",stdin);freopen("hello.out","w",stdout);}
      |                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:61:5: note: in expansion of macro 'fop'
   61 |     fop;
      |     ^~~

• Subtask 1: 25 / 30
• Subtask 2: 45.9375 / 70