[WEEK14] Cheolsoon

WEEK14/BOJ_14466/cheolsoon.java

@@ -0,0 +1,104 @@
+import java.io.*;
+import java.util.*;
+
+import org.omg.CORBA.INTERNAL;
+
+public class Main {
+
+	/*
+	 * 소가 길을 건나간 이유
+	 * N x N
+	 * 인접 목초지 자유롭게 이동한다. 
+	 * 일부는 길을 건너간다. 
+	 * 
+	 * */
+	static int N, K, R;
+	// 상하좌우
+	static int dx[] = {-1,1,0,0};
+	static int dy[] = {0,0,-1,1};
+	static int graph[][];
+	static boolean visited[][];
+	static List<int[]> bridge[][];
+	static List<int[]> cow;
+
+	public static void main(String[] args) throws Exception {
+		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = null;
+		st = new StringTokenizer(in.readLine());
+		N = Integer.parseInt(st.nextToken());
+		K = Integer.parseInt(st.nextToken());
+		R = Integer.parseInt(st.nextToken());
+		graph = new int[N][N];
+		bridge = new ArrayList[N][N];
+		for(int i=0;i<N;i++) {
+			for(int j=0;j<N;j++) {
+				bridge[i][j] = new ArrayList<>();
+			}
+		}
+		cow = new ArrayList<>();
+		int r1,c1,r2,c2;
+		for(int i=0;i<R;i++) {
+			st = new StringTokenizer(in.readLine());
+			r1 = Integer.parseInt(st.nextToken())-1; 
+			c1 = Integer.parseInt(st.nextToken())-1;
+			r2 = Integer.parseInt(st.nextToken())-1;
+			c2 = Integer.parseInt(st.nextToken())-1;
+			bridge[r1][c1].add(new int[] {r2, c2});
+			bridge[r2][c2].add(new int[] {r1, c1});
+		}
+
+		int r,c;
+		for(int i=0;i<K;i++) {
+			st = new StringTokenizer(in.readLine());
+			r = Integer.parseInt(st.nextToken())-1;
+			c = Integer.parseInt(st.nextToken())-1;
+
+			cow.add(new int[] {r, c});
+		}
+
+		int cnt=0;
+		// 소가 한마리씩 길을 건넌다
+		for(int i=0;i<K;i++) {
+			visited = new boolean[N][N];
+			moveCow(cow.get(i));
+
+			for(int j=i;j<K;j++) {
+				int temp[] = cow.get(j);
+				// 방문하지 않은 곳에 소가 있으면 만날 수 없음.
+				if(!visited[temp[0]][temp[1]]) cnt++;
+			}
+		}
+
+		System.out.println(cnt);
+
+	}
+
+	private static void moveCow(int[] pos) {
+		int x = pos[0];
+		int y = pos[1];
+		visited[pos[0]][pos[1]] = true;
+
+		for(int dir=0;dir<4;dir++) {
+			int nx = x+dx[dir];
+			int ny = y+dy[dir];
+
+			if(nx<0 || nx>=N || ny<0 || ny>=N) continue;
+			if(visited[nx][ny]) continue;
+
+//			if(bridge[x][y].contains(new int[] {nx,ny})) continue; ;
+			boolean isBridge = false;
+			for(int k=0;k<bridge[x][y].size();k++) {
+				int temp [] = bridge[x][y].get(k);
+				if(temp[0] == nx && temp[1] == ny) {
+					isBridge = true;
+					break;
+				}
+			}
+
+			if(isBridge) continue;
+
+			moveCow(new int[] {nx, ny});
+		}
+
+	}
+}

WEEK14/BOJ_14466/cheolsoon.md

@@ -0,0 +1,141 @@
+![header](https://capsule-render.vercel.app/api?type=waving&height=200&color=0:FF658D,100:FFCB32&text=BOJ%2014466&fontColor=FFFFFF&fontAlign=80&fontAlignY=35&fontSize=50)
+
+# **🔒Problem**
+
+> [BOJ 14466 소가 길을 건너간 이유 6](https://www.acmicpc.net/problem/14466)
+
+<br>
+<br>
+
+# **💻Code**
+
+```java
+import java.io.*;
+import java.util.*;
+
+import org.omg.CORBA.INTERNAL;
+
+public class Main {
+
+	/*
+	 * 소가 길을 건나간 이유
+	 * N x N
+	 * 인접 목초지 자유롭게 이동한다. 
+	 * 일부는 길을 건너간다. 
+	 * 
+	 * */
+	static int N, K, R;
+	// 상하좌우
+	static int dx[] = {-1,1,0,0};
+	static int dy[] = {0,0,-1,1};
+	static int graph[][];
+	static boolean visited[][];
+	static List<int[]> bridge[][];
+	static List<int[]> cow;
+
+	public static void main(String[] args) throws Exception {
+		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = null;
+		st = new StringTokenizer(in.readLine());
+		N = Integer.parseInt(st.nextToken());
+		K = Integer.parseInt(st.nextToken());
+		R = Integer.parseInt(st.nextToken());
+		graph = new int[N][N];
+		bridge = new ArrayList[N][N];
+		for(int i=0;i<N;i++) {
+			for(int j=0;j<N;j++) {
+				bridge[i][j] = new ArrayList<>();
+			}
+		}
+		cow = new ArrayList<>();
+		int r1,c1,r2,c2;
+		for(int i=0;i<R;i++) {
+			st = new StringTokenizer(in.readLine());
+			r1 = Integer.parseInt(st.nextToken())-1; 
+			c1 = Integer.parseInt(st.nextToken())-1;
+			r2 = Integer.parseInt(st.nextToken())-1;
+			c2 = Integer.parseInt(st.nextToken())-1;
+			bridge[r1][c1].add(new int[] {r2, c2});
+			bridge[r2][c2].add(new int[] {r1, c1});
+		}
+
+		int r,c;
+		for(int i=0;i<K;i++) {
+			st = new StringTokenizer(in.readLine());
+			r = Integer.parseInt(st.nextToken())-1;
+			c = Integer.parseInt(st.nextToken())-1;
+
+			cow.add(new int[] {r, c});
+		}
+
+		int cnt=0;
+		// 소가 한마리씩 길을 건넌다
+		for(int i=0;i<K;i++) {
+			visited = new boolean[N][N];
+			moveCow(cow.get(i));
+
+			for(int j=i;j<K;j++) {
+				int temp[] = cow.get(j);
+				// 방문하지 않은 곳에 소가 있으면 만날 수 없음.
+				if(!visited[temp[0]][temp[1]]) cnt++;
+			}
+		}
+
+		System.out.println(cnt);
+
+	}
+
+	private static void moveCow(int[] pos) {
+		int x = pos[0];
+		int y = pos[1];
+		visited[pos[0]][pos[1]] = true;
+
+		for(int dir=0;dir<4;dir++) {
+			int nx = x+dx[dir];
+			int ny = y+dy[dir];
+
+			if(nx<0 || nx>=N || ny<0 || ny>=N) continue;
+			if(visited[nx][ny]) continue;
+
+//			if(bridge[x][y].contains(new int[] {nx,ny})) continue; ;
+			boolean isBridge = false;
+			for(int k=0;k<bridge[x][y].size();k++) {
+				int temp [] = bridge[x][y].get(k);
+				if(temp[0] == nx && temp[1] == ny) {
+					isBridge = true;
+					break;
+				}
+			}
+
+			if(isBridge) continue;
+
+			moveCow(new int[] {nx, ny});
+		}
+
+	}
+}
+
+```
+
+<br>
+<br>
+
+# **🔑Description**
+
+> 
+
+<br>
+<br>
+
+# **📑Related Issues**
+
+> 
+
+<br>
+<br>
+
+# **🕛Resource**
+
+| Memory    | Time    |
+| --------- | ------- |
+| `28524`KB | `320`ms |

WEEK14/BOJ_20366/cheolsoon.java

@@ -0,0 +1,70 @@
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class Main {
+	/*
+	 * 눈덩이 i의 지름 hi
+	 * 하나의 눈사람 두개 눈덩이
+	 * 아래 눈덩이 >= 위 눈덩이
+	 * 눈덩이 N개 중에 서로 다른 4개 골라서
+	 * 2개의 눈사람 만든다
+	 * 눈사람의 키는 두 눈사람 지름 합과 같다
+	 * 눈사람의 키 차이가 작을수록 사이가 좋다
+	 * 만들 수 있는 눈사람의 키 차이의 최솟값을 구해라
+	 * 
+	 * */
+	static int N, snow[];
+	static boolean used[];
+
+	public static void main(String[] args) throws Exception {
+		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = null;
+
+		N = Integer.parseInt(in.readLine());
+		snow = new int[N];
+		used = new boolean[N];
+
+		st = new StringTokenizer(in.readLine());
+		for(int i=0;i<N;i++) {
+			snow[i] = Integer.parseInt(st.nextToken());
+		}
+
+		Arrays.sort(snow);
+
+		int minDiff = Integer.MAX_VALUE;
+		for(int i=0;i<N-1;i++) {
+			used[i] = true;
+			int snowman1, snowman2;
+			for(int j=i+1;j<N;j++) {
+				used[j] = true;
+				snowman1 = snow[i] + snow[j];
+				// 두개 뽑고 나머지 두개 뽑기
+				int start = 0;
+				int end = N-1;
+				while(start<end) {
+					if(start == i || start == j) {
+						start++;
+						continue;
+					}
+					if(end == i || end == j) {
+						end--;
+						continue;
+					}
+
+					snowman2 = snow[start] + snow[end];
+					minDiff = Math.min(minDiff, Math.abs(snowman1 - snowman2));
+					if(snowman1 > snowman2) {
+						start++;
+					}else {
+						end--;
+					}
+				}
+			}
+		}
+
+		System.out.println(minDiff);
+	}
+
+}