Submission #715649

#	Time	Username	Problem	Language	Result	Execution time	Memory
715649		fatemetmhr	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	419 ms	123452 KiB

tracks

// ~ Be Name Khoda ~
 
#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
//#pragma GCC target("avx2")
//#pragma GCC optimize("unroll-loops,O3")
 
using namespace std;
 
typedef long long ll;
 
#define pb       push_back
#define mp       make_pair
#define all(x)   x.begin(), x.end()
#define fi       first
#define se       second
 
const int maxn  =  1e6   + 10;
const int maxn5 =  4e3   + 10;
const int maxnt =  1.2e6 + 10;
const int maxn3 =  1e3   + 10;
const int mod   =  1e9   +  7;
const ll  inf   =  1e18;
 
int n, m, cnt = 0;
bool mark[maxn5][maxn5];
vector <pair<int, int>> nxt, tmp;
pair<int, int> q[maxn5 * maxn5];
string s[maxn5];
 
void bfs(int xx, int yy){
    int l = 0, r = 1;
    q[0] = {xx, yy};
    mark[xx][yy] = true;
    while(l < r){
        int x = q[l].fi, y = q[l].se;
        l++;
        if(x && !mark[x - 1][y] && s[x - 1][y] != '.'){
            if(s[x - 1][y] == s[x][y]){
                mark[x - 1][y] = true;
                q[r++] = {x - 1, y};
            }
            else
                nxt.pb({x - 1, y});
        }
        if(x + 1 < n && !mark[x + 1][y] && s[x + 1][y] != '.'){
            if(s[x + 1][y] == s[x][y]){
                mark[x + 1][y] = true;
                q[r++] = {x + 1, y};
            }
            else
                nxt.pb({x + 1, y});
        }
        if(y && !mark[x][y - 1] && s[x][y - 1] != '.'){
            if(s[x][y - 1] == s[x][y]){
                mark[x][y - 1] = true;
                q[r++] = {x, y - 1};
            }
            else
                nxt.pb({x, y - 1});
        }
        if(y + 1 < m && !mark[x][y + 1] && s[x][y + 1] != '.'){
            if(s[x][y + 1] == s[x][y]){
                mark[x][y + 1] = true;
                q[r++] = {x, y + 1};
            }
            else
                nxt.pb({x, y + 1});
        }
    }
}
 
int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
 
    cin >> n >> m;
    for(int i = 0; i < n; i++)
        cin >> s[i];
    bfs(0, 0);
    int ans = 1;
    while(nxt.size()){
        ans++;
        tmp.clear();
        for(auto u : nxt)
            tmp.pb(u);
        nxt.clear();
        for(auto u : tmp) if(!mark[u.fi][u.se])
            bfs(u.fi, u.se);
    }
    cout << ans << endl;
}

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