Submission #484889

#	Time	Username	Problem	Language	Result	Execution time	Memory
484889		ali22413836	Tracks in the Snow (BOI13_tracks)	C++14	51.88 / 100	70 ms	36808 KiB

tracks

#include <bits/stdc++.h>
#define  endl "\n"
using namespace std ;
typedef long long ll;
typedef long double ld ;
const int N=2e7;
const ll inf=1e18 ;
const ll mod = 1e9 + 7 ;
ll mypower(ll x, ll y){
    if(y == 0) return 1 ;
    if(y == 1) return x ;
    ll ret = mypower(x , y / 2);
    ret = (ret * ret) % mod;
    if(y % 2) ret = ( ret * x ) % mod ;
    return ret ;
}
ll n , m ;
char a[2000][2000] ;
ll vis[2000][2000] ;
ll sta , sta2 , en , en2 ;
ll di[] = {0 , 0 , 1 , -1} , di2[] = {1 , -1 , 0 , 0} ;
int main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n >> m ;
    for(int i = 0 ; i < n ; i++){
        cin >> a[i] ;
    }
    deque < pair < ll , ll > > q ;
    q.push_back({sta , sta2}) ;
    sta = 0 , sta2 =  0 ;
    vis[sta][sta2] = 1 ;
    ll ans = 0  ;
    while(!q.empty()){
        pair < ll , ll > x  ;
        x = q.front() ;
        q.pop_front() ;
        ans = max(ans , vis[x.first][x.second])  ;
        ll i = x.first , j = x.second ;
        for(int k = 0 ; k < 4 ; k++){
            ll ni = i + di[k] , nj = j + di2[k] ;
            if(ni < n && ni >= 0 && nj < m && nj >= 0 && a[ni][nj] != '.' && vis[ni][nj] == 0){
                if(a[ni][nj] == a[i][j]){
                    q.push_front({ni , nj}) ;
                    vis[ni][nj] = vis[i][j]  ;
                }
                else{
                    q.push_back({ni , nj}) ;
                    vis[ni][nj] = vis[i][j] + 1 ;
                }
             }
        }
    }
    cout << ans << endl ;
    return 0 ;
}

• Subtask 1: 30 / 30
• Subtask 2: 21.875 / 70