[20250918] BOJ / P5 / 뱀 / 이종환

0224LJH/202509/18 BOJ 뱀.md

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+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+
+	static final char LEFT = 'L'; // 감소 
+	static final char RIGHT = 'R'; // 증가
+	static ArrayList<Line> lines = new ArrayList<>();
+
+	static int[] dy = {0,-1,0,1};
+	static int[] dx = {1,0,-1,0};
+
+	static int maxLimit,minLimit,turnCnt,curDir,curX,curY;
+	static long curTime;
+	static Turn[] turns;
+
+	static class Turn{
+		int after;
+		char dir;
+
+		public Turn(int after, String dir) {
+			this.after = after;
+			this.dir = dir.charAt(0);
+		}
+	}
+
+	static class Line{
+		int stX, stY, endX, endY;
+		boolean isVertical;
+
+		public Line(int stX, int stY, int endX, int endY) {
+
+			isVertical = (stX == endX);
+			if (isVertical) {
+				this.stX = this.endX = stX;
+				this.stY = Math.min(stY, endY);
+				this.endY = Math.max(stY, endY);
+			} else {
+				this.stY = this.endY = stY;
+				this.stX = Math.min(stX, endX);
+				this.endX = Math.max(stX, endX);
+			}
+		}
+
+		public boolean check(Line l) {
+			// 둘이 크로스되는지, 아니면 평행한지 부터 판단
+			if (this.isVertical && l.isVertical) {
+				if (this.stX != l.stX) return true;
+				if (this.stY > l.endY || this.endY < l.stY) return true; 
+				return false;
+			} else if (!this.isVertical && !l.isVertical){
+				if (this.stY != l.stY) return true;
+				if (this.stX > l.endX || this.endX < l.stX) return true;
+				return false;
+			}else {
+				if (!this.isVertical) {
+					if((this.stY >= l.stY && this.stY <= l.endY)&&
+							(l.stX >= this.stX && l.stX <= this.endX))return false;
+					return true;
+				} else {
+					if((l.stY >= this.stY && l.stY <= this.endY)&&
+							(this.stX >= l.stX && this.stX <= l.endX))return false;
+					return true;
+				}
+			}
+
+		}
+	}
+
+
+
+
+
+    public static void main(String[] args) throws NumberFormatException, IOException {
+		init();
+		process();
+		print();
+    }
+
+    public static void init() throws NumberFormatException, IOException {
+    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    	maxLimit = Integer.parseInt(br.readLine());
+    	minLimit = maxLimit*(-1);
+    	turnCnt = Integer.parseInt(br.readLine());
+    	turns = new Turn[turnCnt+1];
+    	curDir = 0;
+    	curTime = 0;
+    	curY = 0;
+    	curX = 0;
+
+    	for (int i = 0; i < turnCnt; i++) {
+    		StringTokenizer st = new StringTokenizer(br.readLine());
+    		int after = Integer.parseInt(st.nextToken());
+    		String dir = st.nextToken();
+    		turns[i] = new Turn(after,dir);
+    	}
+
+
+
+
+
+    }
+
+    public static void process() { 	
+    	lines.add(new Line(minLimit, minLimit-1, maxLimit, minLimit-1));
+    	lines.add(new Line(minLimit-1, minLimit, minLimit-1, maxLimit));
+    	lines.add(new Line(maxLimit+1, minLimit, maxLimit+1, maxLimit));
+    	lines.add(new Line(minLimit, maxLimit+1, maxLimit, maxLimit+1));
+
+    	turns[turnCnt] = new Turn(1000000000,"L");
+
+
+    	for(int i = 0 ; i <= turnCnt; i++) {
+    		Turn t = turns[i];
+    		int nX = curX + dx[curDir] * t.after;
+    		int nY = curY + dy[curDir] * t.after;
+    		int minTime = Integer.MAX_VALUE;
+    		boolean isOkay = true;
+
+
+    		Line nLine = new Line(curX, curY, nX, nY);
+
+    		for (Line l: lines) {
+
+    			if(!l.check(nLine)) {
+    				int tempMin = Integer.MAX_VALUE;
+
+    				if(curDir == 0) tempMin = Math.min(tempMin, l.stX - curX);
+    				if(curDir == 1) tempMin = Math.min(tempMin,  curY - l.endY);
+    				if(curDir == 2) tempMin = Math.min(tempMin, curX - l.endX);
+    				if(curDir == 3) tempMin = Math.min(tempMin, l.stY - curY);
+
+
+    				if (tempMin == 0) continue;
+    				isOkay = false;
+    				minTime = Math.min(minTime, tempMin);
+    			}
+    		}
+
+    		lines.add(nLine);
+
+
+    		if (isOkay) {
+    			curTime += t.after;
+    			if (t.dir == LEFT) curDir = (curDir +3)%4;
+    			else curDir = (curDir+1)%4;
+
+    			curX = nX;
+    			curY = nY;
+    		} else {
+    			curTime += minTime;
+    			return;
+    		}
+
+    	}
+
+    }
+
+
+
+
+	public static void print() {
+		System.out.println(curTime);
+    }
+}