Merge pull request #57 from ottffss1005/main

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Author: ottffss1005

Soyoung/week1/Baek_11720

@@ -0,0 +1,28 @@
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+
+        Scanner sc = new Scanner(System.in);
+
+        //System.out.println("사이즈 입력: ");
+        int size = sc.nextInt(); //size 입력받기
+        sc.nextLine();
+
+        //int[] arr = new int[size]; //size 크기에 맞는 배열 생성
+        //System.out.println("숫자 공백없이 입력");
+        String num = sc.nextLine().trim(); //12345
+
+        int sum=0;
+        for(int i=0;i<size; i++){
+            char c = num.charAt(i);
+            //sum += c;
+            sum += Character.getNumericValue(c);
+        }
+
+        System.out.println(sum);
+        sc.close();
+
+    }
+}

Soyoung/week1/Baek_1546

@@ -0,0 +1,41 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+       // System.out.print("과목 수 입력: ");
+        int sub = sc.nextInt(); //시험 본 과목의 개수 N
+        int[] arr = new int[sub]; //시험 본 과목의 배열
+        double[] arr2 = new double[sub]; //조작된 시험 배열
+        int max = 0; //최고점
+
+        for(int i=0;i<sub;i++){
+            arr[i] = sc.nextInt();
+            //System.out.print("arr[] ");
+            //System.out.print(arr[i]+" ");
+        }
+
+        //max에 최대값 넣기
+        for(int i=0;i<sub;i++){
+            if(arr[i]>max){
+                max=arr[i];
+            }
+        }
+
+        //System.out.println(max+" 이게 max입니다.");
+
+        for(int i=0;i<sub;i++){
+            arr2[i] = (arr[i]/(double)max) *100;
+            //System.out.print("arr2: "+arr2[i]+" ");
+        }
+
+        double sum = Arrays.stream(arr2).sum();
+
+        double new_avg = sum/sub;
+
+        System.out.println(new_avg);
+
+    }
+}

Soyoung/week2/BOJ_11659

@@ -0,0 +1,42 @@
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.io.IOException;
+import java.util.StringTokenizer;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+
+        //입력 받기
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        //집합 크기 n, 합 개수 m 받아오기
+        int n = Integer.parseInt(st.nextToken());
+        int m = Integer.parseInt(st.nextToken());
+
+        //그때그때 입력받으면 runtimeerror 뜸
+        // 그래서 미리 합을 구해놓으면 편함
+
+        //arr은 집합 저장 배열 pre_sum은 누적합 저장 배열
+        int[] arr = new int[n + 1];
+        int[] pre_sum = new int[n + 1];
+
+        st = new StringTokenizer(br.readLine());
+        //집합 누적합 계산
+        for (int i = 1; i <= n; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+            pre_sum[i] = pre_sum[i - 1] + arr[i];
+        }
+
+        for (int i = 0; i < m; i++) {
+            st = new StringTokenizer(br.readLine());
+            int j = Integer.parseInt(st.nextToken());
+            int q = Integer.parseInt(st.nextToken());
+
+            int sum = pre_sum[q] - pre_sum[j - 1];
+            System.out.println(sum);
+        }
+    }
+
+}

Soyoung/week7/BOJ_11724

@@ -0,0 +1,50 @@
+package study;
+import java.util.*;
+import java.io.*;
+
+public class BOJ_11724 {
+    static ArrayList<Integer>[] graph;
+    static boolean[] visited;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        int N = Integer.parseInt(st.nextToken()); // 정점 개수
+        int M = Integer.parseInt(st.nextToken()); // 간선 개수
+
+        graph = new ArrayList[N+1];
+        visited = new boolean[N+1];
+
+        for (int i = 1; i <= N; i++) {
+            graph[i] = new ArrayList<>();
+        }
+
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int u = Integer.parseInt(st.nextToken());
+            int v = Integer.parseInt(st.nextToken());
+            graph[u].add(v);
+            graph[v].add(u);
+        }
+
+        int count = 0;
+        for (int i = 1; i <= N; i++) {
+            if (!visited[i]) {
+                dfs(i);
+                count++;
+            }
+        }
+
+        System.out.println(count);
+    }
+
+    public static void dfs(int node) {
+        visited[node] = true;
+        for (int next : graph[node]) {
+            if (!visited[next]) {
+                dfs(next);
+            }
+        }
+    }
+}

Soyoung/week7/BOJ_2023

@@ -0,0 +1,45 @@
+package study;
+import java.io.*;
+
+public class BOJ_2023 {
+
+    static int N; // 자릿수
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine().trim());
+
+        // 1자리 소수에서 시작
+        int[] PrimeStarts = {2, 3, 5, 7};
+        for (int s : PrimeStarts) {
+            dfs(s, 1);
+        }
+    }
+
+    // DFS
+    static void dfs(int num, int depth) {
+        if (depth == N) {
+            System.out.println(num);
+            return;
+        }
+
+        // 뒷자리 후보 리스트
+        int[] PrimeEnds = {1, 3, 7, 9};
+        for (int d : PrimeEnds) {
+            int next = num * 10 + d;
+            if (isPrime(next)) {
+                dfs(next, depth + 1);
+            }
+        }
+    }
+
+    // 소수 판별
+    static boolean isPrime(int n) {
+        if (n < 2) return false;
+        //axb=c이면 루트cx루트c니까 a 혹은 b는 루트 c보다 하나는 무조건 작고 하나는 큼
+        for (int i = 2; i * i <= n; i++) {
+            if (n % i == 0) return false;
+        }
+        return true;
+    }
+}