Submission #76040

#	Time	Username	Problem	Language	Result	Execution time	Memory
76040		tmwilliamlin168	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1204 ms	901464 KiB

tracks

#include <bits/stdc++.h>
using namespace std;

const int mxN=4e3;
int n, m, ans, nb[4][2]={{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
string g[mxN];
vector<array<int, 2>> tp[2];

__attribute__((always_inline)) bool a(int i, int j) {
	return i>=0&&i<n&&j>=0&&j<m&&g[i][j]!='.';
}

void dfs(int i, int j) {
	char pc=g[i][j];
	g[i][j]='.';
	for(int k=0; k<4; ++k) {
		int ni=i+nb[k][0], nj=j+nb[k][1];
		if(!a(ni, nj))
			continue;
		if(g[ni][nj]==pc)
			dfs(ni, nj);
		else
			tp[ans&1^1].push_back({ni, nj});
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n >> m;
	for(int i=0; i<n; ++i)
		cin >> g[i];
	tp[0].push_back({0, 0});
	for(; tp[ans&1].size(); ++ans) {
		for(array<int, 2> u : tp[ans&1])
			if(a(u[0], u[1]))
				dfs(u[0], u[1]);
		tp[ans&1].clear();
	}
	cout << ans;
}

Compilation message (stderr)

tracks.cpp: In function 'void dfs(int, int)':
tracks.cpp:23:10: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
    tp[ans&1^1].push_back({ni, nj});
       ~~~^~
tracks.cpp: At global scope:
tracks.cpp:9:37: warning: always_inline function might not be inlinable [-Wattributes]
 __attribute__((always_inline)) bool a(int i, int j) {
                                     ^

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