#include "bits/stdc++.h"
using namespace std;
#define int long long
#define pb emplace_back
#define mx(a, b) ((a) > (b) ? (a) : (b))
#define mn(a, b) ((a) < (b) ? (a) : (b))
#define graph(n) vector<int> g[(n)+1];
constexpr int mod = 1000000007;
void frx(std::string name) {
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
/*
template <typename T, size_t N>
std::ostream &operator<<(std::ostream &os, const T (&arr)[N]) {
os << "[";
for(size_t i = 0; i < N; ++i) {
if(i>0) {
os << ", ";
}
os<<arr[i];
}
return os << "]";
}
*/
int h,w;
char a[4001][4001];
bool is(int i, int j) {
return i>=0 && i<h && j>=0 && j<w && a[i][j]!='.';
}
void solve() {
cin >> h >> w;
for(int i = 0; i < h; ++i) {
for(int j = 0; j < w; ++j) {
cin>>a[i][j];
}
}
int dist[h][w];
for(int i = 0; i < h; ++i) {
for(int j = 0; j < w; ++j) {
dist[i][j] = 1e18;
}
}
dist[0][0] = 1;
deque<pair<int,int>> q;
q.push_front({0,0});
int ans = 0;
while(!q.empty()) {
int x = q.front().first;
int y = q.front().second;
q.pop_front();
ans=mx(ans, dist[x][y]);
if(is(x-1,y)) {
if(dist[x-1][y] >dist[x][y]+(a[x][y] != a[x-1][y])) {
dist[x-1][y] = dist[x][y]+(a[x][y] != a[x-1][y]);
if(a[x][y] != a[x-1][y]) {
q.push_back({x-1,y});
} else {
q.push_front({x-1,y});
}
}
}
if(is(x+1,y)) {
if(dist[x+1][y] > dist[x][y]+(a[x][y] != a[x+1][y])) {
dist[x+1][y] = dist[x][y]+(a[x][y] != a[x+1][y]);
if(a[x][y] != a[x+1][y]) {
q.push_back({x+1,y});
} else {
q.push_front({x+1,y});
}
}
}
if(is(x,y-1)) {
if(dist[x][y-1] > dist[x][y]+(a[x][y] != a[x][y-1])) {
dist[x][y-1] = dist[x][y]+(a[x][y] != a[x][y-1]);
if(a[x][y] != a[x][y-1]) {
q.push_back({x,y-1});
} else {
q.push_front({x,y-1});
}
}
}
if(is(x,y+1)) {
if(dist[x][y+1] > dist[x][y]+(a[x][y] != a[x][y+1])) {
dist[x][y+1] = dist[x][y]+(a[x][y] != a[x][y+1]);
if(a[x][y] != a[x][y+1]) {
q.push_back({x,y+1});
} else {
q.push_front({x,y+1});
}
}
}
}
std::cout<<ans<<"\n";
}
signed main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
//frx("perimeter");
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
auto start = std::chrono::high_resolution_clock::now();
#endif
int t = 1;
//std::cin >> t;
while (t--) {
solve();
}
#ifdef LOCAL
auto end = std::chrono::high_resolution_clock::now();
std::chrono::duration<double> elapsed = end - start;
std::cout << elapsed.count() << " seconds\n";
#endif
return 0;
}
Compilation message
tracks.cpp: In function 'void frx(std::string)':
tracks.cpp:13:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
13 | freopen((name + ".in").c_str(), "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:14:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
14 | freopen((name + ".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
4440 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
604 KB |
Output is correct |
4 |
Correct |
6 ms |
3932 KB |
Output is correct |
5 |
Correct |
2 ms |
2140 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
604 KB |
Output is correct |
8 |
Correct |
1 ms |
604 KB |
Output is correct |
9 |
Correct |
1 ms |
860 KB |
Output is correct |
10 |
Correct |
2 ms |
1796 KB |
Output is correct |
11 |
Correct |
2 ms |
1628 KB |
Output is correct |
12 |
Correct |
4 ms |
2268 KB |
Output is correct |
13 |
Correct |
2 ms |
2140 KB |
Output is correct |
14 |
Correct |
3 ms |
2304 KB |
Output is correct |
15 |
Correct |
9 ms |
4664 KB |
Output is correct |
16 |
Correct |
10 ms |
4444 KB |
Output is correct |
17 |
Correct |
8 ms |
4280 KB |
Output is correct |
18 |
Correct |
6 ms |
3980 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
15680 KB |
Output is correct |
2 |
Correct |
41 ms |
19036 KB |
Output is correct |
3 |
Correct |
301 ms |
157088 KB |
Output is correct |
4 |
Correct |
77 ms |
40788 KB |
Output is correct |
5 |
Correct |
201 ms |
91216 KB |
Output is correct |
6 |
Correct |
693 ms |
183240 KB |
Output is correct |
7 |
Correct |
8 ms |
16312 KB |
Output is correct |
8 |
Correct |
6 ms |
15708 KB |
Output is correct |
9 |
Correct |
2 ms |
860 KB |
Output is correct |
10 |
Correct |
1 ms |
604 KB |
Output is correct |
11 |
Correct |
7 ms |
16220 KB |
Output is correct |
12 |
Correct |
1 ms |
1244 KB |
Output is correct |
13 |
Correct |
41 ms |
19100 KB |
Output is correct |
14 |
Correct |
30 ms |
11892 KB |
Output is correct |
15 |
Correct |
20 ms |
12892 KB |
Output is correct |
16 |
Correct |
17 ms |
7516 KB |
Output is correct |
17 |
Correct |
110 ms |
43856 KB |
Output is correct |
18 |
Correct |
74 ms |
43344 KB |
Output is correct |
19 |
Correct |
73 ms |
40640 KB |
Output is correct |
20 |
Correct |
59 ms |
37456 KB |
Output is correct |
21 |
Correct |
155 ms |
94552 KB |
Output is correct |
22 |
Correct |
179 ms |
91216 KB |
Output is correct |
23 |
Correct |
192 ms |
78404 KB |
Output is correct |
24 |
Correct |
185 ms |
92568 KB |
Output is correct |
25 |
Correct |
285 ms |
156852 KB |
Output is correct |
26 |
Correct |
402 ms |
222212 KB |
Output is correct |
27 |
Correct |
520 ms |
191808 KB |
Output is correct |
28 |
Correct |
677 ms |
183372 KB |
Output is correct |
29 |
Correct |
662 ms |
184040 KB |
Output is correct |
30 |
Correct |
603 ms |
182984 KB |
Output is correct |
31 |
Correct |
426 ms |
103884 KB |
Output is correct |
32 |
Correct |
520 ms |
187912 KB |
Output is correct |