Junsu

junsu/week14/BOJ1238 파티/BOJ1238.java

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+//BOJ1238 파티, 골드3
+//다익스트라 알고리즘
+//목적지로 간 후 다시 되돌아오는 거라서 다익스트라 목적지에서 시작점으로 한번 더 써주면 된다.
+//visited 안쓴 버전
+//실수한부분 - pq.add 위치 잘못씀;
+//pq.add(new Node(next.to, dist[next.to]));
+import java.io.*;
+import java.util.*;
+
+public class BOJ1238 {
+	static class Node implements Comparable<Node>{
+		int to;
+		int cost;
+
+		public Node(int to, int cost) {
+			this.to = to;
+			this.cost = cost;
+		}
+
+		@Override
+		public int compareTo(Node o) {
+			return this.cost - o.cost;
+		}
+	}
+	static int N, M, X, MaxAns;
+	static int[] dist;
+	static boolean[] visited;
+	static int INF = 987654321;
+	static ArrayList<Node>[] nodeList;
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		X = Integer.parseInt(st.nextToken());
+		nodeList = new ArrayList[N+1];
+		for(int i = 1; i <= N; i++) {
+			nodeList[i] = new ArrayList<>();
+		}
+
+		for(int i = 0; i < M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int from = Integer.parseInt(st.nextToken());
+			int to = Integer.parseInt(st.nextToken());
+			int cost = Integer.parseInt(st.nextToken());
+			nodeList[from].add(new Node(to, cost));
+		}
+
+		int temp;
+		for(int i = 1; i <= N; i++) {
+			dijstra(i);
+			temp = dist[X];
+			//파티후 귀가
+			dijstra(X);
+			temp += dist[i];
+
+			MaxAns = Math.max(MaxAns, temp);
+//			bw.write(MaxAns+"\n");
+		}
+
+		bw.write(MaxAns+"\n");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+
+	// 파티하러 X 마을로 출발
+	static void dijstra(int start) {
+		dist = new int[N+1];
+		Arrays.fill(dist, INF);
+
+//		//다익스트라 알고리즘
+		PriorityQueue<Node> pq = new PriorityQueue<>();
+		pq.add(new Node(start, 0));
+		dist[start] = 0;
+
+		while(!pq.isEmpty()) {
+			Node curNode = pq.poll();
+			int cur = curNode.to;
+			int cost = curNode.cost;
+
+			for(Node next : nodeList[cur]) {
+				if(dist[next.to] > dist[cur] + next.cost) {
+					dist[next.to] = dist[cur] + next.cost;
+					pq.add(new Node(next.to, dist[next.to]));
+				}
+//				실수한부분 - pq.add 위치 잘못씀;
+//				pq.add(new Node(next.to, dist[next.to])); 
+			}
+		}
+
+	}
+}

junsu/week14/BOJ1261 알고스팟/BOJ1261.java

@@ -0,0 +1,92 @@
+//BOJ1261 알고스팟, 골드4
+//다익스트라 알고리즘, 벽 부수고 이동하기랑 비슷
+//최단경로가 아닌 벽 부순 갯수 기준이라서 우선순위 큐 써야함
+import java.io.*;
+import java.util.*;
+
+public class BOJ1261 {
+	static class Node implements Comparable<Node>{
+		int x;
+		int y;
+		int cost;
+
+		public Node(int x, int y, int cost) {
+			this.x = x;
+			this.y = y;
+			this.cost = cost;
+		}
+		@Override
+		public int compareTo(Node o) {
+			return this.cost - o.cost;
+		}
+	}
+	static int N, M, ans;
+	static int[][] map;
+	static int INF = 987654321;
+	static int[] dx = {0, 1, 0, -1}; //우 하 좌 상
+	static int[] dy = {1, 0, -1, 0};
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		M = Integer.parseInt(st.nextToken());
+		N = Integer.parseInt(st.nextToken());
+
+		map = new int[N+1][M+1];
+
+		for(int i = 1; i <= N; i++) {
+//			st = new StringTokenizer(br.readLine());
+//			String temp = st.nextToken();
+			String temp = br.readLine();
+			for(int j = 1; j <= M; j++) {
+				map[i][j] = temp.charAt(j-1) - '0';
+			}
+		}
+
+//		for(int i = 1; i <= N; i++) {
+//			for(int j = 1; j <= M; j++) {
+//				System.out.print(map[i][j] + " ");
+//			}
+//			System.out.println();
+//		}
+		ans = dijkstra();
+
+		bw.write(ans + "\n");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+    static int dijkstra() {
+        PriorityQueue<Node> pq = new PriorityQueue<>();
+        pq.add(new Node(1, 1, 0)); // x, y, 벽을 부순 횟수
+        boolean[][] visit  = new boolean[N+1][M+1];
+        visit[1][1] =true;
+
+        while (!pq.isEmpty()) {
+            Node cur = pq.poll();
+            int curX = cur.x;
+            int curY = cur.y;
+            int curCost = cur.cost;
+
+            if (curX == N && curY == M) {
+            	return curCost;
+            }
+
+            for (int dic = 0; dic < 4; dic++) {
+                int nextX = curX + dx[dic];
+                int nextY = curY + dy[dic];
+                if (nextX <= 0 || nextY <= 0 || nextX > N || nextY > M) continue;
+
+                if(!visit[nextX][nextY] && map[nextX][nextY] == 0) {
+                	visit[nextX][nextY] = true;
+                	pq.add(new Node(nextX, nextY, curCost));
+                }
+                if(!visit[nextX][nextY] && map[nextX][nextY] == 1) {
+                	visit[nextX][nextY] = true;
+                	pq.add(new Node(nextX, nextY, curCost+1));
+                }
+            }
+        }
+        return 0;
+    }
+}

junsu/week14/BOJ14284 간선 이어가기2/BOJ14284.java

@@ -0,0 +1,76 @@
+//BOJ14284 간선 이어가기2, 골드5
+//데이크스트라 알고리즘
+import java.io.*;
+import java.util.*;
+
+public class BOJ14284 {
+	static class Node implements Comparable<Node>{
+		int to;
+		int cost;
+		public Node(int to, int cost) {
+			this.to = to;
+			this.cost = cost;
+		}
+		@Override
+		public int compareTo(Node o) {
+			return this.cost - o.cost;
+		}
+	}
+	static int N, M, ans;
+	static ArrayList<Node>[] nodeList;
+	static int[] dist;
+	static int INF = 987654321;
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		dist = new int[N+1];
+		nodeList = new ArrayList[N+1];
+		for(int i = 1; i <= N; i++) {
+			dist[i] = INF;
+			nodeList[i] = new ArrayList<>();
+		}
+
+		for(int i = 0; i < M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			int c = Integer.parseInt(st.nextToken());
+			nodeList[a].add(new Node(b, c));
+			nodeList[b].add(new Node(a, c));
+		}
+
+		st = new StringTokenizer(br.readLine());
+		int s = Integer.parseInt(st.nextToken());
+		int t = Integer.parseInt(st.nextToken());
+
+		dijkstra(s, t);
+
+		bw.write(ans + "\n");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+	static void dijkstra(int start, int end) {
+		PriorityQueue<Node> pq = new PriorityQueue<>();
+		pq.add(new Node(start, 0));
+		dist[start] = 0;
+
+		while(!pq.isEmpty()) {
+			Node curNode = pq.poll();
+			int cur = curNode.to;
+			int cost = curNode.cost;
+
+			for(Node next : nodeList[cur]) {
+				if(dist[next.to] > dist[cur] + next.cost) {
+					dist[next.to] = dist[cur] + next.cost;
+					pq.add(new Node(next.to, dist[next.to]));
+				}
+			}
+		}
+		ans = dist[end];
+	}
+}

junsu/week14/BOJ14719 빗물/BOJ14719.java

@@ -0,0 +1,85 @@
+//BOJ14719 빗물, 골드5
+//구현, 시뮬레이션 문제
+//구현 문제라서 크게 피드백이 없다.
+// 처음에 빈 공간과 이미 방문한 곳을 동시에 처리해서 에러가 발생했다.
+// 빈 공간과 이미 방문한 곳을 따로 처리해줘야함
+import java.io.*;
+import java.util.*;
+
+public class BOJ14719 {
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		int H = Integer.parseInt(st.nextToken());
+		int W = Integer.parseInt(st.nextToken());
+		int[][] map = new int[H+1][W+1];
+		boolean[][] visited = new boolean[H+1][W+1];
+
+		st = new StringTokenizer(br.readLine());
+		for(int i = 1; i <= W; i++) {
+			int num = Integer.parseInt(st.nextToken());
+			int cnt = 0;
+			for(int j = H; j >= 1; j--) {
+				if(cnt++ == num) break;
+				map[j][i] = 1;
+			}
+		}
+
+//		for(int i = 1; i <= H; i++) {
+//			for(int j = 1; j <= W; j++) {
+//				System.out.print(map[i][j] + " ");
+//			}
+//			System.out.println();
+//		}
+
+		int ans = 0;
+		int N, M, endN, endM;
+		Loop1 :
+		for(int i = 1; i <= H; i++) {
+			N = M = endN = endM = 0;
+			for(int j = 1; j <= W; j++) {
+				if(H == 1 && W == 1) {
+					break Loop1;
+				}
+				// 빈 공간
+				if(map[i][j] == 0) continue;
+
+				// 이미 방문한 곳은 N과 M 리셋해줘야함
+				if(visited[i][j]) {
+					N = 0;
+					M = 0;
+					continue;
+				}
+
+				//블록 처음 발견했을때
+				if(N == 0 && M == 0) {
+					N = i;
+					M = j;
+				}else { //끝 블록 발견했을때
+					endN = i;
+					endM = j;
+//					System.out.println("시작"+N+ " " + endN+ " "+M+" "+endM);
+
+					//실수한 부분 : x, y 범위 설정을 잘못 생각함
+					for(int x = i; x <= i; x++) {
+						for(int y = M + 1; y < endM; y++) { 
+							visited[x][y] = true;
+							if(map[x][y] == 0) {
+//								System.out.println(x + " " + y);
+								ans++;
+							}
+						}
+					}
+					N = M = endN = endM = 0;
+					j--;
+				}
+			}
+		}
+		bw.write(ans+"\n");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+}