Submission #681751

#	Time	Username	Problem	Language	Result	Execution time	Memory
681751		vjudge1	Tracks in the Snow (BOI13_tracks)	C++11	100 / 100	1299 ms	123780 KiB

tracks

#include<iostream>
#include<deque>
using namespace std;
const int maxn = 4005;
int n,m,ans,val[maxn][maxn];
char arr[maxn][maxn];
deque<pair<int,int> > bfs;
void goTo(int oX, int oY, int x, int y) {
    if(x < 0 || x >= n || y < 0 || y >= m) return;
    if(val[x][y] != 0 || arr[x][y] == '.') return;
    if(arr[oX][oY] == arr[x][y]) {
        bfs.push_front(make_pair(x,y));
        val[x][y] = val[oX][oY];
    }
    else {
        bfs.push_back(make_pair(x,y));
        val[x][y] = val[oX][oY]+1;
    }
}
int main () {
    scanf("%d%d",&n,&m);
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            scanf(" %c",&arr[i][j]);
        }
    }
    val[0][0] = 1;
    bfs.push_front(make_pair(0,0));
    while(bfs.size() > 0) {
        pair<int,int> pos = bfs.front();
        bfs.pop_front();
        ans = max(ans,val[pos.first][pos.second]);
        goTo(pos.first,pos.second,pos.first-1,pos.second);
        goTo(pos.first,pos.second,pos.first+1,pos.second);
        goTo(pos.first,pos.second,pos.first,pos.second-1);
        goTo(pos.first,pos.second,pos.first,pos.second+1);
    }
    printf("%d\n",ans);
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:21:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
tracks.cpp:24:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |             scanf(" %c",&arr[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~

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