[Week01] BOJ_10828: 스택

weekly/week01/BOJ_10828_스택/sukangpunch.java

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+package stduy.week01;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+// 스택
+public class BOJ_10828 {
+    static class MyStack{
+        int [] st;
+        int top;
+
+        public MyStack(int size){
+            this.st = new int[size];
+            this.top = -1;
+        }
+
+        public void push(int x){
+            st[++top] = x;
+        }
+
+        public int pop(){
+            if(top == -1){
+                return -1;
+            }
+
+            return st[top--];
+        }
+
+        public int size(){
+            return top + 1;
+        }
+
+        public int empty(){
+            if(top == -1){
+                return 1;
+            }
+
+            return 0;
+        }
+
+        public int top(){
+            if(top == -1){
+                return -1;
+            }
+
+            return st[top];
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb = new StringBuilder();
+
+        int N = Integer.parseInt(br.readLine());
+
+        MyStack stack = new MyStack(N);
+        for (int i = 0; i < N; i++) {
+            String []s = br.readLine().split(" ");
+
+            switch(s[0]){
+                case "push": stack.push(Integer.parseInt(s[1])); break;
+                case "pop": sb.append(stack.pop()).append("\n"); break;
+                case "size": sb.append(stack.size()).append("\n"); break;
+                case "empty": sb.append(stack.empty()).append("\n"); break;
+                case "top": sb.append(stack.top()).append("\n"); break;
+            }
+        }
+        System.out.println(sb);
+    }
+}

weekly/week01/BOJ_1920_수 찾기/sukangpunch.java

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+package stduy.week01;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+public class BOJ_1920 {
+
+    static int [] A;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb = new StringBuilder();
+
+        int N = Integer.parseInt(br.readLine());
+        String [] s = br.readLine().split(" ");
+        A = new int[N];
+        for(int i=0;i<N;i++){
+            A[i] = Integer.parseInt(s[i]);
+        }
+        Arrays.sort(A);
+
+        int M = Integer.parseInt(br.readLine());
+        s = br.readLine().split(" ");
+
+        for(int i=0;i<M;i++){
+            int num = Integer.parseInt(s[i]);
+            int result = findNumByBinarySearch(0, N - 1, num);
+            sb.append(result).append("\n");
+        }
+
+        System.out.println(sb);
+
+    }
+
+    private static int findNumByBinarySearch(int start, int end, int target) {
+        if(start > end){
+            return 0;
+        }
+
+        int mid = (start + end) / 2;
+
+        if(A[mid] == target){
+            return 1;
+        }else if(A[mid] > target){
+            return findNumByBinarySearch(start, mid - 1, target);
+        }else{
+            return findNumByBinarySearch(mid + 1, end, target);
+        }
+    }
+
+}