Submission #776249

#	Time	Username	Problem	Language	Result	Execution time	Memory
776249		amine_aroua	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	653 ms	137276 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define vl vector<long long>
#define vii vector<pair<int,int>>
#define vll vector<pair<long long,long long>>
#define pb push_back
#define ll long long
#define ld long double
#define nl '\n'
#define boost ios::sync_with_stdio(false)
#define mp make_pair
#define se second
#define fi first
#define fore(i, y) for(int i = 0; i < y; i++)
#define forr(i,x,y) for(int i = x;i<=y;i++)
#define forn(i,y,x) for(int i = y; i >= x; i--)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define clr(v,k) memset(v,k,sizeof(v))
#define rall(v) v.rbegin() , v.rend()
#define pii pair<int,int>
#define pll pair<ll , ll>

const ll MOD = 1e9 + 7;
const ll INF = 1e9 + 1;

ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return a * (b / gcd(a , b));} // least common multiple (PPCM)

// HERE IS THE SOLUTION
vii coor = {{0 , 1} , {1 , 0}  ,{-1 , 0} , {0 , -1}};
int main()
{
    cin.tie(0);
    cout.tie(0);
    boost;
    int n , m;
    cin>>n>>m;
    char grid[n][m];
    fore(i , n)
    {
        fore(j , m)
        {
            cin>>grid[i][j];
        }
    }
    int dist[n][m];
    pii cur  = {0 , 0};
    fore(i , n)
    {
        fore(j , m)
        {
            dist[i][j] = INF;
        }
    }
    dist[0][0] = 0;
    deque<pii> dq;
    dq.push_front(cur);
    while(!dq.empty())
    {
        pii node = dq.front();
        dq.pop_front();
        for(auto  p: coor)
        {
            int nx = p.fi + node.fi , ny = p.se + node.se;
            if(nx < 0 || ny < 0 || nx>=n || ny>=m || grid[nx][ny] == '.')continue;
            int w = 0;
            if(grid[nx][ny] != grid[node.fi][node.se])
                w = 1;
            if(dist[nx][ny] > dist[node.fi][node.se] + w)
            {
                dist[nx][ny] = w + dist[node.fi][node.se];
                if(w == 0)
                    dq.push_front({nx , ny});
                else
                    dq.push_back({nx , ny});
            }
        }
    }
    int ans = 0;
    fore(i , n)
    {
        fore(j , m)
        {
            if(grid[i][j] != '.')
                ans = max(ans , dist[i][j]);
        }
    }
    cout<<ans +1<<nl;
}

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