Submission #377156

#	Time	Username	Problem	Language	Result	Execution time	Memory
377156		pavement	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	920 ms	128420 KiB

tracks

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
//#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef double db;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

int H, W, ans, dr[] = {-1, 0, 0, 1}, dc[] = {0, -1, 1, 0};
char tmp, prv, F[4005][4005];
bool vis[4005][4005];
deque<ii> Q;

main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> H >> W;
	for (int i = 1; i <= H; i++)
		for (int j = 1; j <= W; j++) {
			cin >> tmp;
			if (tmp == '.') tmp = 2;
			else if (tmp == 'R') tmp = 0;
			else tmp = 1;
			F[i][j] = tmp;
		}
	Q.eb(1, 1);
	prv = F[1][1];
	while (!Q.empty()) {
		auto [r, c] = Q.front();
		Q.pop_front();
		if (vis[r][c]) continue;
		vis[r][c] = 1;
		if (F[r][c] != prv) ans++;
		prv = F[r][c];
		for (int k = 0; k < 4; k++) {
			int nr = r + dr[k], nc = c + dc[k];
			if (1 <= nr && nr <= H && 1 <= nc && nc <= W && F[nr][nc] != 2 && !vis[nr][nc]) {
				if (F[nr][nc] != F[r][c]) Q.eb(nr, nc);
				else Q.emplace_front(nr, nc);
			}
		}
	}
	cout << ++ans << '\n';
}

Compilation message (stderr)

tracks.cpp:33:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   33 | main() {
      |      ^

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