제출 #971327

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
971327		Bodisha	Tracks in the Snow (BOI13_tracks)	C++17	86.88 / 100	2121 ms	1048576 KiB

tracks

#include <bits/stdc++.h>
#define MAX_D 4000
#define MAX_D 4000

using namespace std;

int h, w;
char meadow[MAX_D][MAX_D];
int component[MAX_D][MAX_D];
vector<int> graph[MAX_D * MAX_D];
int d[MAX_D * MAX_D];
set<pair<int, int>> edges;
queue<int> q;

void floodfill(int x, int y, int cmp) {
    component[x][y] = cmp;
    if(x + 1 < h && meadow[x + 1][y] == meadow[x][y] && component[x + 1][y] == 0) {
        floodfill(x + 1, y, cmp);
    }
    if(x - 1 >= 0 && meadow[x - 1][y] == meadow[x][y] && component[x - 1][y] == 0) {
        floodfill(x - 1, y, cmp);
    }
    if(y + 1 < w && meadow[x][y + 1] == meadow[x][y] && component[x][y + 1] == 0) {
        floodfill(x, y + 1, cmp);
    }
    if(y - 1 >= 0 && meadow[x][y - 1] == meadow[x][y] && component[x][y - 1] == 0) {
        floodfill(x, y - 1, cmp);
    }
}

int main() {
    string tmps;
    cin >> h >> w;
    for(int i = 0; i < h; i++) {
        cin >> tmps;
        for(int j = 0; j < w; j++) {
            meadow[i][j] = tmps[j];
        }   
    }
    int cnt = 1;
    for(int i = 0; i < h; i++) {
        for(int j = 0; j < w; j++) {
            if(component[i][j] == 0 && meadow[i][j] != '.') {
                floodfill(i, j, cnt);
                cnt++;
            }
        }
    }
    for(int i = 0; i < h; i++) {
        for(int j = 0; j < w; j++) {
            if(meadow[i][j] == '.') {
                continue;
            }
            if(i + 1 < h && meadow[i + 1][j] != '.' && component[i + 1][j] != component[i][j] && edges.count({component[i][j], component[i + 1][j]}) == 0) {
                graph[component[i + 1][j]].push_back(component[i][j]);
                graph[component[i][j]].push_back(component[i + 1][j]);
                edges.insert({component[i + 1][j], component[i][j]});
                edges.insert({component[i][j], component[i + 1][j]});
            }
            if(i - 1 >= 0 && meadow[i - 1][j] != '.' && component[i - 1][j] != component[i][j] && edges.count({component[i][j], component[i - 1][j]}) == 0) {
                graph[component[i - 1][j]].push_back(component[i][j]);
                graph[component[i][j]].push_back(component[i - 1][j]);
                edges.insert({component[i - 1][j], component[i][j]});
                edges.insert({component[i][j], component[i - 1][j]});
            }  
            if(j + 1 < w && meadow[i][j + 1] != '.' && component[i][j + 1] != component[i][j] && edges.count({component[i][j], component[i][j + 1]}) == 0) {
                graph[component[i][j + 1]].push_back(component[i][j]);
                graph[component[i][j]].push_back(component[i][j + 1]);
                edges.insert({component[i][j], component[i][j + 1]});
                edges.insert({component[i][j + 1], component[i][j]});
            }  
            if(j - 1 >= 0 && meadow[i][j - 1] != '.' && component[i][j - 1] != component[i][j] && edges.count({component[i][j], component[i][j - 1]}) == 0) {
                graph[component[i][j - 1]].push_back(component[i][j]);
                graph[component[i][j]].push_back(component[i][j - 1]);
                edges.insert({component[i][j], component[i][j - 1]});
                edges.insert({component[i][j - 1], component[i][j]});
            }     
        }
    }
    fill(d, d + cnt, -1);
    d[component[0][0]] = 0;
    q.push(component[0][0]);
    while(!q.empty()) {
        int curr_node = q.front();
        q.pop();
        for(auto iter : graph[curr_node]) {
            if(d[iter] == -1) {
                d[iter] = d[curr_node] + 1;
                q.push(iter);
            }
        }
    }
    int ans = 1;
    for(int i = 0; i < cnt; i++) {
        ans = max(ans, d[i] + 1);
    }
    cout << ans;
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 56.875 / 70