Submission #438482

#	Time	Username	Problem	Language	Result	Execution time	Memory
438482		zeyu	Tracks in the Snow (BOI13_tracks)	C++17	2.19 / 100	84 ms	80744 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n, m;
	cin >> n >> m;
	vector<string> graph(n);
	for (int i = 0; i < n; i ++) cin >> graph[i];
	int cnt[n][m];
	int inf = 0x3f3f3f3f;
	memset(cnt, inf, sizeof(cnt));
	cnt[0][0] = 1;
	queue<pair<int, int> > que;
	que.push(make_pair(0, 0));
	while(! que.empty()){
		pair<int, int> p = que.front();
		que.pop();
		for (int i = 0; i < 4; i ++){
			int x = p.first + dx[i];
			int y = p.second + dy[i];
			if (x >= 0 && x < n && y >= 0 && y < m && cnt[x][y] > cnt[p.first][p.second] + (graph[x][y] != graph[p.first][p.second])){
				que.push(make_pair(x, y));
				cnt[p.first][p.second] += graph[x][y] != graph[p.first][p.second];
			}
		}
	}
	int ans = inf;
	for (int i = 0; i < n; i ++){
		for (int j = 0; j < m; j ++) ans = min(ans, cnt[i][j]);
	}
	cout << ans << endl;
}

• Subtask 1: 0 / 30
• Subtask 2: 2.1875 / 70