[11657.🚀](https://boj.kr/11657)
2 |
3 | 시간은 과거에서 현재로, 현재에서 미래로만 향한다는 뜻이다. 아직까지 시간이 미래에서 현재로, 현재에서 과거로 역류한 예는 없었다. 따라서 어떤 기계를 만들더라도 이러한 시간의 비가역성을 바꾸어놓을 수 없으므로 타임머신은 불가능하다
4 |
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/programmers/월간코드챌린지시즌3/없는숫자더하기/ch.java:
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1 | public class ch {
2 | public int solution(int[] numbers) {
3 | int answer = 45;
4 |
5 | for(int i = 0; i < numbers.length; i++){
6 | answer -= numbers[i];
7 | }
8 | return answer;
9 | }
10 | }
11 |
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/programmers/월간코드챌린지시즌1/내적/chan.java:
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1 | class chan {
2 | public int solution(int[] a, int[] b) {
3 | int answer = 0;
4 |
5 | for (int i = 0; i < a.length; i++) {
6 | answer += (a[i] * b[i]);
7 | }
8 |
9 | return answer;
10 | }
11 | }
12 |
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/programmers/코딩테스트연습/124 나라의 숫자/ch_12899.java:
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1 | public class ch_12899 {
2 | public String solution(int n) {
3 | String[] num = {"4", "1", "2"};
4 | String answer = "";
5 |
6 | while (n > 0) {
7 | answer = num[n % 3] + answer;
8 | // 3으로 나누어 떨어질 땐 -1
9 | n = (n - 1) / 3;
10 | }
11 | return answer;
12 | }
13 | }
14 |
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/BOJ/2292.벌집/chan.java:
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1 | import java.util.Scanner;
2 |
3 | public class chan {
4 |
5 | public static void main(String[] args) {
6 | Scanner sc = new Scanner(System.in);
7 | int N = sc.nextInt();
8 |
9 | int i = 0;
10 | int end = 1;
11 | while (true) {
12 | end = end + (6 * i);
13 | if (N <= end) break;
14 | i++;
15 | }
16 | System.out.println(i + 1);
17 | sc.close();
18 | }
19 |
20 | }
21 |
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/BOJ/1261.algospot/readme.md:
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1 | [](https://www.acmicpc.net/problem/1261)
2 |
3 |
12 | * 중복조합
13 | */
14 | public class oh_16922 {
15 | static int N, R, count;
16 | static boolean[] check;
17 | static int[] ch;
18 | static int[] input;
19 | static Set set;
20 | public static void main(String[] args) throws IOException {
21 | BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
22 | R = Integer.parseInt(br.readLine());
23 | N = 4;
24 | count = 0;
25 | check = new boolean[N];
26 | ch = new int[]{1,5,10,50};
27 | input = new int[R];
28 | set= new HashSet();
29 | Dfs(0, 0);
30 | System.out.println(set.size());
31 | }
32 |
33 | private static void Dfs(int cnt, int start) {
34 | if (cnt == R) {
35 | int sum=0;
36 | for (int c : input) {
37 |
38 | sum+=c;
39 | }
40 | set.add(sum);
41 |
42 | return;
43 | }
44 | for (int i = start; i < check.length; i++) {
45 |
46 |
47 | check[i] = true;
48 | input[cnt] = ch[i];
49 | Dfs(cnt + 1, i);
50 | check[i] = false;
51 |
52 |
53 | }
54 | }
55 | }
56 |
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/BOJ/10819. 차이를 최대로/haeun_10819.java:
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1 | import java.io.BufferedReader;
2 | import java.io.IOException;
3 | import java.io.InputStreamReader;
4 | import java.util.StringTokenizer;
5 |
6 | public class BOJ_10819_차이를최대로 {
7 |
8 | public static int N, max;
9 | public static int[] A, arr;
10 | public static boolean[] checked;
11 |
12 | public static void main(String[] args) throws IOException {
13 | BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
14 | N = Integer.parseInt(br.readLine()); // N개의 정수
15 | A = new int[N]; // 입력받는 배열
16 | arr = new int[N];
17 | checked = new boolean[N];
18 |
19 | StringTokenizer st = new StringTokenizer(br.readLine(), " ");
20 | // 배열 채우기
21 | for (int i = 0; i < N; i++) {
22 | A[i] = Integer.parseInt(st.nextToken());
23 | }
24 | // 최댓값을 최소로 초기화
25 | max = Integer.MIN_VALUE;
26 |
27 | perm(0);
28 | // 출력
29 | System.out.println(max);
30 | }
31 |
32 | // 순열
33 | public static void perm(int num) {
34 | // 기저조건
35 | if (num == N) {
36 | // 주어진 식대로 계산
37 | int sum = 0;
38 | for (int i = 0; i < N-1; i++) {
39 | sum += Math.abs(arr[i] - arr[i+1]);
40 | }
41 | // 최댓값 갱신
42 | if (sum > max) max = sum;
43 | return;
44 | }
45 |
46 | for (int i = 0; i < N; i++) {
47 | if (checked[i]) continue;
48 | arr[num] = A[i];
49 | checked[i] = true;
50 | perm(num + 1);
51 | checked[i] = false;
52 | }
53 | }
54 | }
55 |
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/BOJ/1106.호텔/ch_1106.java:
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1 | import java.io.BufferedReader;
2 | import java.io.IOException;
3 | import java.io.InputStreamReader;
4 | import java.util.Arrays;
5 | import java.util.StringTokenizer;
6 |
7 | public class ch_1106 {
8 | public static void main(String[] args) throws IOException {
9 | BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
10 | StringTokenizer st = new StringTokenizer(br.readLine());
11 | final int INF = 987654321;
12 |
13 | int C = Integer.parseInt(st.nextToken());
14 | int N = Integer.parseInt(st.nextToken());
15 |
16 | int[] cost = new int[N + 1];
17 | int[] customer = new int[N + 1];
18 | int[] DP = new int[C + 101];
19 | Arrays.fill(DP, INF);
20 | DP[0] = 0;
21 |
22 | for (int i = 1; i <= N; i++) {
23 | st = new StringTokenizer(br.readLine());
24 | cost[i] = Integer.parseInt(st.nextToken());
25 | customer[i] = Integer.parseInt(st.nextToken());
26 | }
27 |
28 | for (int i = 1; i <= N; i++) {
29 | for (int j = customer[i]; j < C + 101; j++) {
30 | DP[j] = Math.min(DP[j], cost[i] + DP[j - customer[i]]);
31 | }
32 | }
33 |
34 | int min = INF;
35 | for (int i = C; i < C + 101; i++) {
36 | min = Math.min(min, DP[i]);
37 | }
38 |
39 | System.out.println(min);
40 | }
41 | }
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/BOJ/2467. 용액/ch_2467.java:
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1 | import java.io.BufferedReader;
2 | import java.io.IOException;
3 | import java.io.InputStreamReader;
4 | import java.util.Arrays;
5 | import java.util.StringTokenizer;
6 |
7 | public class ch_2467 {
8 | static int N, a = 0, b = 0, min = Integer.MAX_VALUE;
9 | static int[] arr;
10 | public static void main(String[] args) throws IOException {
11 | BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
12 | N = Integer.parseInt(br.readLine());
13 | arr = new int[N];
14 | StringTokenizer st = new StringTokenizer(br.readLine());
15 | for (int i = 0; i < N; i++) {
16 | arr[i] = Integer.parseInt(st.nextToken());
17 | }
18 | Arrays.sort(arr);
19 |
20 | for (int i = 0; i < N; i++) {
21 | int left = i + 1;
22 | int right = N - 1;
23 | while (left <= right){
24 | int mid = (left + right) / 2;
25 | int sum = Math.abs(arr[i] + arr[mid]);
26 |
27 | if (min > sum) {
28 | min = sum;
29 | a = arr[i];
30 | b = arr[mid];
31 | }
32 | if (arr[mid] == -arr[i]) break;
33 | else if (arr[mid] < -arr[i]) left = mid + 1;
34 | else right = mid - 1;
35 | }
36 | }
37 | System.out.println(a + " " + b);
38 | }
39 | }
40 |
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/BOJ/21921. 블로그/haeun_21921.java:
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1 | import java.io.BufferedReader;
2 | import java.io.IOException;
3 | import java.io.InputStreamReader;
4 | import java.util.StringTokenizer;
5 |
6 | public class BOJ_21921_블로그 {
7 |
8 | public static void main(String[] args) throws IOException {
9 | BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
10 | StringTokenizer st = new StringTokenizer(br.readLine(), " ");
11 |
12 | int N = Integer.parseInt(st.nextToken()); // 블로그 시작한지 N일
13 | int X = Integer.parseInt(st.nextToken()); // X일 탐색
14 |
15 | int[] people = new int[N]; // 방문자 수
16 | st = new StringTokenizer(br.readLine(), " ");
17 | for (int i = 0; i < N; i++) people[i] = Integer.parseInt(st.nextToken());
18 |
19 | int max; // 최대 방문자 수
20 | int term = 1; // 기간 수(초기 1)
21 | int sum = 0; // 최댓값과 비교할 sum 변수
22 |
23 | // 방문자들의 합 계산
24 | for (int i = 0; i < X; i++) {
25 | sum += people[i];
26 | }
27 | max = sum;
28 |
29 | // 슬라이딩 윈도우
30 | for (int i = X; i < N; i++) {
31 | sum += people[i] - people[i - X];
32 |
33 | // 최댓값 갱신
34 | if (max < sum) {
35 | max = sum;
36 | // 기간 초기화
37 | term = 1;
38 | }
39 | // 기간 + 1
40 | else if (max == sum) term++;
41 | }
42 |
43 | // 출력
44 | if (max == 0) System.out.println("SAD");
45 | else {
46 | System.out.println(max); // 최대 방문자 수
47 | System.out.println(term); // 기간
48 | }
49 | }
50 | }
51 |
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/SWEA/10912. 외로운 문자/oh.java:
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1 | import java.io.BufferedReader;
2 | import java.io.IOException;
3 | import java.io.InputStreamReader;
4 | import java.io.StringReader;
5 | import java.util.ArrayList;
6 |
7 | public class Expert10912 {
8 | public static void main(String[] args) throws IOException {
9 | BufferedReader br =new BufferedReader(new InputStreamReader(System.in));
10 |
11 | int T = Integer.parseInt(br.readLine());
12 | for (int test_case = 1; test_case <= T; test_case++) {
13 | //알파벳을 인덱스 값으로 쓴다
14 | int[] alpha = new int[26];
15 | String str = br.readLine();
16 | for (int i = 0; i < str.length(); i++) {
17 | alpha[str.charAt(i)-'a']++;
18 |
19 | }
20 | // 홀수만 따로 배열에 담는다
21 | ArrayList