Submission #1120759

#	Time	Username	Problem	Language	Result	Execution time	Memory
1120759		vjudge1	Tracks in the Snow (BOI13_tracks)	C++17	Compilation error	0 ms	0 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<    
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
 
const int inf = 2e18,MOD = 1e9+7;
 
void solve() {
  int n,m;
  cin >> n >> m;
  char grid[n][m];
  for (int i=0;i<n;i++) {
    string s;
    cin >> s;
    for (int j = 0;j<m;j++) grid[i][j] = s[j];
  }
  int dist[n][m];
  for (int i=0;i<n;i++) for (int j = 0;j<m;j++) dist[i][j] = inf;
  deque<pii> dq;
  dist[n-1][m-1] = 1;
  dq.push_front({n-1,m-1});
  vi dx = {0,1,0,-1},dy = {1,0,-1,0};
  while (!dq.empty()) {
    pii f = dq.front();
    dq.pop_front();
    int x = f.ff,y = f.ss;
    for (int i = 0;i<4;i++) {
      int gx = x+dx[i],gy = y+dy[i];
      if (gx < 0 || gx >= n || gy < 0 || gy >= m) continue;
      if (grid[gx][gy] == '.') continue;
      if (dist[gx][gy] <= dist[x][y]+(grid[gx][gy] != grid[x][y])) continue;
      dist[gx][gy] = dist[x][y]+(grid[gx][gy] != grid[x][y]);
      if (grid[gx][gy] == grid[x][y]) dq.push_front({gx,gy});
      else dq.push_back({gx,gy});
    }
  }
  int ans = 0;
  for (int i=0;i<n;i++) for (int j = 0;j<m;j++) if (dist[i][j] != inf) ans = max(ans,dist[i][j]);
  cout << ans << '\n';
}                    
                             
int main() { 
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    int t = 1;
    //cin >> t; 
    while (t --> 0) solve();
}

Compilation message (stderr)

cc1plus: error: '::main' must return 'int'