[BOJ 3197] 백조의 호수 resolve/2

src/week3/BOJ3197/BOJ3197_V3.cpp

@@ -0,0 +1,96 @@
+#include <bits/stdc++.h>
+using namespace std;
+int r,c;
+bool swan_visited[1500][1500];
+bool water_visited[1500][1500];
+char inp[1500][1500];
+int dy[4] = {0,0,1,-1};
+int dx[4] = {1,-1,0,0};
+queue<pair<int,int> > swan, next_swan;
+queue<pair<int,int> > water, next_water;
+void clear_queue() {
+    swan = next_swan;
+    water = next_water;
+    next_swan = queue<pair<int,int> >();
+    next_water = queue<pair<int,int> >();
+}
+int main() {
+
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+    cout.tie(nullptr);
+
+
+    cin >> r >> c;
+    bool flag = true;
+    for (int i = 0; i < r; i++) {
+        string s;
+        cin >> s;
+        for (int j = 0; j < c; j++) {
+            inp[i][j] = s[j];
+            if (inp[i][j] != 'X') {
+                water.push({i,j});
+                water_visited[i][j] = true;
+            }
+
+            if (inp[i][j] == 'L' && flag) {
+                flag = false;
+                swan.push({i,j});
+                swan_visited[i][j] = true;
+                inp[i][j] = '.';
+            }
+        }
+    }
+    int cnt = 0;
+    while(true) {
+        while(!swan.empty()) {
+            pair<int, int> curr = swan.front();
+            swan.pop();
+
+            if (inp[curr.first][curr.second] == 'L') {
+                cout << cnt << '\n';
+                return 0;
+            }
+
+            for (int i = 0; i < 4; i++) {
+                int ny = curr.first + dy[i];
+                int nx = curr.second + dx[i];
+
+                if (ny < 0 || nx < 0 || ny >= r || nx >= c || swan_visited[ny][nx]) continue;
+
+                if (inp[ny][nx] == 'X') {
+                    swan_visited[ny][nx] = true;
+                    next_swan.push({ny,nx});
+                } else {
+                    swan_visited[ny][nx] = true;
+                    swan.push({ny,nx});
+                }
+            }
+        }
+        while(!water.empty()) {
+            pair<int, int> curr = water.front();
+            water.pop();
+
+            for (int i = 0; i < 4; i++) {
+                int ny = curr.first + dy[i];
+                int nx = curr.second + dx[i];
+
+                if (ny < 0 || nx < 0 || ny >= r || nx >= c || water_visited[ny][nx]) continue;
+
+                if (inp[ny][nx] == 'X') {
+                    water_visited[ny][nx] = true;
+                    inp[ny][nx] = '.';
+                    next_water.push({ny,nx});
+                } else {
+                    water_visited[ny][nx] = true;
+                    water.push({ny,nx});
+                }
+            }
+        }
+        clear_queue();
+        cnt++;
+    }
+
+
+    return 0;
+}