答案應該是對的 只是用的時間過長 

問有沒有大佬知道怎麼 簡化

我的CODE:

import java.util.Scanner;

public class a746 {
    public static void main(String[] args){
         Scanner input = new Scanner(System.in);
         while (input.hasNextInt()){
             int n = input.nextInt();
             int m = input.nextInt();
             String[][] answer = new String[n][n];
             int x1=-1; int y1=-1;
             for (int i =0;i<m;i++){
                int x2=input.nextInt();
                int y2=input.nextInt(); //要往前的點
                if ((x1<x2||y1<y2) && (x1!=-1&&y1!=-1)) { //如果要去位置比自己大的點
                    for(int e=y1-1;e<y2;e++){ //則由小變大
                        for (int q=x1-1;q<x2;q++){
                          answer[e][q] = "*";
                        }
                    }
                }
                if ((x1>x2 || y1>y2)&& (x1!=-1&&y1!=-1)){
                    for(int e=y1-1;e>=y2-1;e--){ //則由大到小
                        for (int q=x1-1;q>=x2-1;q--){
                            answer[e][q] = "*";
                        }
                    }
                }
                x1=x2;//把終點變為起始點
                y1=y2;
             }
             for (int i=0;i<n+2;i++){
                 System.out.print("-");
             }
             System.out.println("");
             for (int q=0;q<answer[0].length;q++){
                 System.out.print("|");
                 for (int e=0;e<answer.length;e++){
                     if (answer[e][q]==null) {
                        System.out.print(" ");
                     } else{
                     System.out.print(answer[e][q]);};
                 }
                 System.out.print("|\n");
             }
             for (int i=0;i<n+2;i++) {
                 System.out.print("-");
             }
             System.out.println("");
         }
    }
}