<Algorithm> 26. 1010번 다리놓기

1. 1010번 다리놓기

• nCr로 풀 수 있다. 공식 n!/r!(n-r)!

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import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.math.BigInteger; import java.util.ArrayList; import java.util.StringTokenizer;   public class Main {        public static void main(String[] args) throws NumberFormatException, IOException {                    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));          StringTokenizer st;          ArrayList<BigInteger> resultList = new ArrayList<>();                    int N = Integer.parseInt(br.readLine());                    for(int T = 0; T < N; T++) {              BigInteger res = new BigInteger("1");                            st = new StringTokenizer(br.readLine());              int r = Integer.parseInt(st.nextToken());              int n = Integer.parseInt(st.nextToken());                                        for(int i = 0; i < r; i++) {                  res = res.multiply(BigInteger.valueOf(n-i));                  // n * n-1 * n-2 ~~ * n-r+1                  res = res.divide(BigInteger.valueOf(i+1));                  // r!              }                            resultList.add(res);          }                   for(BigInteger b:resultList) {             System.out.println(b);         }      }      } Colored by Color Scripter

cs

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.StringTokenizer;
 
public class AA {
 
    public static void main(String[] args) throws IOException {
        
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        ArrayList<BigInteger> list = new ArrayList<>();
        int N = Integer.parseInt(br.readLine());
         
        for(int t = 0 ; t < N; t ++) {
            BigInteger bg = new BigInteger("1");
            BigInteger bg2 = new BigInteger("1");
            
             st = new StringTokenizer(br.readLine());
             int r = Integer.parseInt(st.nextToken());
             int n = Integer.parseInt(st.nextToken());             
            
             
            for(int i = n; i > r; i--) {
                bg = bg.multiply(bg.valueOf(i));
                bg2 = bg2.multiply(bg.valueOf(i-r));
                System.out.println(bg.valueOf(i)+" "+bg.valueOf(i-r)+" ");
            }
            list.add(bg.divide(bg2));    
        }
        
        for(BigInteger bg : list)
            System.out.println(bg);
    }
}