1주차 : 배열 문제 풀이

Author: seyeon22222

Array/.gitkeep

@@ -0,0 +1,16 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int n = Integer.parseInt(br.readLine());
+		String[] input = br.readLine().split(" ");
+		List<String> arr = new ArrayList<>(Arrays.asList(input));
+        String k = br.readLine();
+
+        System.out.println(Collections.frequency(arr, k));
+    }
+}

Array/10807-개수세기.java

@@ -0,0 +1,21 @@
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String input = br.readLine();
+        int[] arr = new int[28];
+        for (int i = 0; i < input.length(); ++i) {
+            arr[input.charAt(i) - 'a']++;
+        }
+
+        for (int i = 0; i < 26; ++i) {
+            System.out.print(arr[i] + " ");
+        }
+    }
+}
+
+

Array/10808-알파벳개수.java

@@ -0,0 +1,26 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String input = br.readLine();
+        int[] arr = new int[10];
+
+        for (int i = 0; i < input.length(); ++i) {
+            int temp = input.charAt(i) - '0';
+            if (temp == 6 || temp == 9)  {
+                if (arr[6] == arr[9]) {
+                    arr[6]++;
+                } else {
+                    arr[9]++;
+                }
+            } else {
+                arr[temp]++;
+            }
+        }
+        System.out.println(Arrays.stream(arr).max().getAsInt());
+    }
+}

Array/1475-방번호.java

@@ -0,0 +1,24 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int ans = 1;
+        for (int i = 0; i < 3; ++i) {
+            int input = Integer.parseInt(br.readLine());
+            ans *= input;
+        }
+
+        String result = String.valueOf(ans);
+        int[] arr = new int[10];
+        for (int i = 0; i < result.length(); ++i) {
+            arr[result.charAt(i) - '0']++;
+        }
+        for (int i = 0; i < 10; ++i)  {
+            System.out.println(arr[i]);
+        }
+    }
+}

Array/2577-숫자의개수.java

@@ -0,0 +1,32 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int n = Integer.parseInt(br.readLine());
+        int[] arr = new int[n];
+        String[] input = br.readLine().split(" ");
+        int ans = 0;
+        for (int i = 0; i < n; ++i) {
+            arr[i] = Integer.parseInt(input[i]);
+        }
+        Arrays.sort(arr);
+        int k = Integer.parseInt(br.readLine());
+        int left = 0;
+        int right = n - 1;
+        while (left < right) {
+            int sum = arr[left] + arr[right];
+            if (sum == k) {
+                ans++; left++; right--;
+            } else if (sum < k) {
+                left++;
+            } else {
+                right--;
+            }
+        }
+        System.out.println(ans);
+    }
+}

Array/3273-두수의합.java

@@ -0,0 +1,34 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String[] input = br.readLine().split(" ");
+        int n = Integer.parseInt(input[0]);
+        int k = Integer.parseInt(input[1]);
+
+        Map<Integer, Integer> s = new HashMap<>();
+        Map<Integer, Integer> f = new HashMap<>();
+
+        for (int i = 0; i < n; ++i) {
+            input = br.readLine().split(" ");
+            int b = Integer.parseInt(input[0]);
+            int a = Integer.parseInt(input[1]);
+            if (b == 0) {
+                s.put(a, s.getOrDefault(a, 0) + 1);
+            } else {
+                f.put(a, f.getOrDefault(a, 0) + 1);
+            }
+        }
+        int ans = 0;
+        for (Map<Integer, Integer> map : List.of(s, f)) {
+            for (int count : map.values()) {
+                ans += (count + k - 1) / k;
+            }
+        }
+        System.out.println(ans);
+    }
+}