Update 0x09-BOJ

0x08_스택의_활용(수식의_괄호_쌍)/Application/10799-쇠막대기.cpp

@@ -9,7 +9,7 @@ int main(){
         if (c == '(') { // 열리는 괄호면 일단 push
             s.push(c);
             stick++; 
-        } else { // 닫히는 괄호 
+        } else { //  c == ')'
             if ( s.top() == '(') { // 레이저
                 s.push(c);
                 stick--; 

0x09_BFS/Prac/1926-그림.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <queue>
+#define X first 
+#define Y second
+
+int board[502][502];
+int vis[502][502];
+int dx[4] = {1,0,-1,0};
+int dy[4] = {0,1,0,-1};
+
+int main(){
+    // std::ios::sync_with_stdio(false);
+    // std::cin.tie(nullptr);
+
+    int r,c;
+    std::cin >> r >> c;
+    std::queue<std::pair<int,int>> q;
+
+    for (int i = 0 ; i < r ; i++){
+        for (int j = 0; j < c ; j++){
+            std::cin >> board[i][j];
+        }
+    }
+    int num = 0;
+    int mxArea = 0;
+    for (int i = 0; i < r; i++){
+        for(int j = 0 ; j < c ; j++){
+            if (board[i][j] == 0 || vis[i][j] == 1) continue;
+            else {
+                vis[i][j] = 1;
+                num++;
+                q.push({i,j});
+                int area = 0;
+                while(!q.empty()){
+                    std::pair<int,int> cur = q.front(); q.pop(); area++;
+                    for(int dir = 0 ; dir < 4 ; dir++){
+                        int nx = cur.X + dx[dir];
+                        int ny = cur.Y + dy[dir];
+                        if(vis[nx][ny] || board[nx][ny] != 1) continue; 
+                        vis[nx][ny] = 1; 
+                        q.push({nx,ny});
+                    }
+                }
+                if ( mxArea < area ) mxArea = area;
+            }
+        }
+    } std::cout << num << "\n" << mxArea;
+}

0x09_BFS/Prac/2178-미로탐색.cpp

@@ -0,0 +1,38 @@
+#include <iostream>
+#include <queue>
+#include <algorithm>
+
+int N,M;
+std::string board[102]; 
+int dist[102][102];
+int dx[4] = {1,0,-1,0};
+int dy[4] = {0,1,0,-1};
+
+int main(){
+
+    std::ios::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin >> N >> M;
+    for (int i = 0 ; i < N ; i++) {
+        std::cin >> board[i];
+    }
+    for(int i = 0; i < N; i++) 
+        std::fill(dist[i],dist[i]+M,-1);
+
+    std::queue<std::pair<int,int>> q;
+    q.push({0,0});
+    dist[0][0] = 0;
+    while(!q.empty()){
+        auto cur = q.front(); q.pop();
+        for(int dir = 0 ; dir < 4; dir++){
+            int nx = cur.first + dx[dir];
+            int ny = cur.second + dy[dir];
+            if (nx < 0 || ny < 0 || nx >= N || ny >= M ) continue;
+            if (dist[nx][ny] >= 0 || board[nx][ny] != '1') continue;
+            dist[nx][ny] = dist[cur.first][cur.second] + 1;
+            q.push({nx,ny});
+        }
+    }
+    std::cout << dist[N-1][M-1] + 1;
+}

0x09_BFS/Prac/7576-토마토.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <queue>
+
+int board[1002][1002] ;
+int dis[1002][1002];
+
+int dx[4] = {1,0,-1,0};
+int dy[4] = {0,-1,0,1};
+
+int n,m;
+
+int main(){
+
+    std::queue<std::pair<int,int> > q; 
+    std::cin >> m >> n ;
+    for (int i = 0 ; i < n ; i++){
+        for (int j = 0; j < m; j++){
+            std::cin >> board[i][j];
+            if ( board[i][j] == 1) q.push({i,j});
+            if ( board[i][j] == 0) dis[i][j] = -1;
+        }
+    }
+
+    while(!q.empty()){
+        auto cur = q.front(); q.pop();
+        for(int dir = 0 ; dir < 4; dir++){
+            int nx = cur.first + dx[dir];
+            int ny = cur.second + dy[dir];
+            if ( nx < 0 || ny < 0 || nx >= n || ny >= m) continue;
+            if ( dis[nx][ny] >= 0 ) continue;
+            dis[nx][ny] = dis[cur.first][cur.second] + 1;
+            q.push({nx,ny});
+        }
+    }
+    int maxDist = 0;
+    for (int i = 0 ; i < n; i++){
+        for (int j = 0 ; j < m;  j++){
+            // std::cout << dis[i][j] ;
+            if (dis[i][j] == -1) {
+                std::cout << -1 ;
+                return 0;
+            }
+            if (dis[i][j] > maxDist) maxDist = dis[i][j]; 
+        }
+        // std::cout << "\n";
+    }
+    std::cout << maxDist ;
+}

0x09_BFS/Prac/BFS.cpp

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define X first
+#define Y second // pair에서 first, second를 줄여서 쓰기 위해서 사용
+int board[502][502] =
+{{1,1,1,0,1,0,0,0,0,0},
+ {1,0,0,0,1,0,0,0,0,0},
+ {1,1,1,0,1,0,0,0,0,0},
+ {1,1,0,0,1,0,0,0,0,0},
+ {0,1,0,0,0,0,0,0,0,0},
+ {0,0,0,0,0,0,0,0,0,0},
+ {0,0,0,0,0,0,0,0,0,0} }; // 1이 파란 칸, 0이 빨간 칸에 대응
+bool vis[502][502]; // 해당 칸을 방문했는지 여부를 저장
+int n = 7, m = 10; // n = 행의 수, m = 열의 수
+int dx[4] = {1,0,-1,0};
+int dy[4] = {0,1,0,-1}; // 상하좌우 네 방향을 의미
+int main(void){
+  ios::sync_with_stdio(0);
+  cin.tie(0);
+  queue<pair<int,int> > Q;
+  vis[0][0] = 1; // (0, 0)을 방문했다고 명시
+  Q.push({0,0}); // 큐에 시작점인 (0, 0)을 삽입.
+  while(!Q.empty()){
+    pair<int,int> cur = Q.front(); Q.pop();
+    cout << '(' << cur.X << ", " << cur.Y << ") -> ";
+    for(int dir = 0; dir < 4; dir++){ // 상하좌우 칸을 살펴볼 것이다.
+      int nx = cur.X + dx[dir];
+      int ny = cur.Y + dy[dir]; // nx, ny에 dir에서 정한 방향의 인접한 칸의 좌표가 들어감
+      if(nx < 0 || nx >= n || ny < 0 || ny >= m) continue; // 범위 밖일 경우 넘어감
+      if(vis[nx][ny] || board[nx][ny] != 1) continue; // 이미 방문한 칸이거나 파란 칸이 아닐 경우
+      vis[nx][ny] = 1; // (nx, ny)를 방문했다고 명시
+      Q.push({nx,ny});
+    }
+  }
+}

0x09_BFS/Prac/test.cpp

@@ -0,0 +1,50 @@
+#include <iostream>
+#include <queue>
+
+using namespace std;
+#define X first
+#define Y second
+int board[1002][1002];
+int dist[1002][1002];
+int n,m;
+int dx[4] = {1,0,-1,0};
+int dy[4] = {0,1,0,-1};
+int main(void){
+  ios::sync_with_stdio(0);
+  cin.tie(0);
+  cin >> m >> n;
+  queue<pair<int,int>> Q;
+  for(int i = 0; i < n; i++){
+    for(int j = 0; j < m; j++){
+      cin >> board[i][j];
+      if(board[i][j] == 1)
+        Q.push({i,j});
+      if(board[i][j] == 0)
+        dist[i][j] = -1;
+    }
+  }
+  while(!Q.empty()){
+    auto cur = Q.front(); Q.pop();
+    for(int dir = 0; dir < 4; dir++){
+      int nx = cur.X + dx[dir];
+      int ny = cur.Y + dy[dir];
+      if(nx < 0 || nx >= n || ny < 0 || ny >= m) continue;
+      if(dist[nx][ny] >= 0) continue;
+      dist[nx][ny] = dist[cur.X][cur.Y]+1;
+      Q.push({nx,ny});
+    }
+  }
+  int maxDist = 0;
+  for (int i = 0 ; i < n; i++){
+        for (int j = 0 ; j < m;  j++){
+            std::cout << dist[i][j] ;
+            if (dist[i][j] == -1) {
+                std::cout << -1 ;
+                return 0;
+            }
+            if (dist[i][j] > maxDist) maxDist = dist[i][j]; 
+        }
+        std::cout << "\n";
+    }
+    std::cout << maxDist;
+}

0x09_BFS/readme.md

@@ -0,0 +1 @@
+# 0x09_BFS