Submission #1228161

#	Time	Username	Problem	Language	Result	Execution time	Memory
1228161		sitingfake	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	684 ms	127028 KiB

tracks

#include<bits/stdc++.h>
using namespace std;

// define

#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ld double
#define ii pair<int,int>
#define se second
#define fi first
#define iii pair<int,ii>
#define all(v) v.begin(),v.end()
#define bit(x,i) (((x)>>(i))&1LL)
#define flip(x,i) ((x)^(1LL<<(i)))
#define ms(d,x) memset(d,x,sizeof(d))
#define sitingfake 1
#define orz 1
#define visit visited
#define left __left
#define right __right

//constant

const ll mod = 1e9 + 7;
const long long linf = 4557430888798830399;
const int inf = 1061109567;
const int maxarr = 1e6 + 5;
int dx[] = {0 , -1 , 0 , 1};
int dy[] = {-1 , 0 , 1 , 0};

template<typename T> bool maximize(T &a, const T &b)
{
    if(a < b) {a = b; return 1;}
    return 0;
}

template<typename T> bool minimize(T &a, const T &b)
{
    if(a > b) {a = b; return 1;}
    return 0;
}

inline void Plus(ll & a ,ll b)
{
    b %= mod;
    a += b;
    if(a >= mod) a -= mod;
    if(a < 0) a += mod;
    return;
}

inline void Mul(ll & a, ll b)
{
    a %= mod; b %= mod;
    a *= b;
    a %= mod;
    return;
}

//code

const int maxn = 4e3 + 5;

char a[maxn][maxn];

int dist[maxn][maxn];

int n , m;

void solve(void)
{
    cin >> n >> m;

    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            cin >> a[i][j];
        }
    }

    deque <ii> q;
    ms(dist , 0x3f);
    dist[1][1] = 1;
    q.push_front(ii(1 , 1));

    while(!q.empty())
    {
        int u = q.front().fi;
        int v = q.front().se;

        q.pop_front();

        for(int i = 0; i < 4; i++)
        {
            int x = u + dx[i];
            int y = v + dy[i];

            if(1 <= x && x <= n && 1 <= y && y <= m && a[x][y] != '.')
            {
                int w = a[u][v] != a[x][y];
                if(minimize(dist[x][y] , dist[u][v] + w))
                {
                    if(w) q.push_back(ii(x , y));
                    else q.push_front(ii(x , y));
                }
            }
        }
    }

    int ans = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            if(dist[i][j] != inf)
            {
                ans = max(ans , dist[i][j]);
            }
        }
    }

    cout << ans;
}
/**
**/
signed main()
{
   ios_base::sync_with_stdio(0);
   cin.tie(0);
   cout.tie(0);

   #define task ""

   if(fopen(task".inp","r"))
   {
       freopen(task".inp","r",stdin);
       freopen(task".out","w",stdout);
   }

   int tc; tc = 1;

   while(tc--) solve();

   //execute;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:138:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |        freopen(task".inp","r",stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:139:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |        freopen(task".out","w",stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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