baekjoon 20251212

code_study/Baekjoon/java/_16724.java

@@ -0,0 +1,68 @@
+import java.util.*;
+
+public class _16724 {
+    static char[][] mapInfo = new char[1000][1000];
+    static int[] parents = new int[1000000];
+    static int[] rank = new int[1000000];
+    static int N, M;
+
+    static int area_num(int i, int j) {
+        return M*i + j;
+    }
+
+    static int find(int n) {
+        if (n != parents[n]) return parents[n] = find(parents[n]);
+        return n;
+    }
+
+    static void union(int a, int b) {
+        a = find(a);
+        b = find(b);
+
+        if (a != b) {
+            if (rank[a] > rank[b]) parents[b] = a;
+            else if (rank[a] < rank[b]) parents[a] = b;
+            else {
+                parents[a] = b;
+                rank[b]++;
+            }
+        }
+    }
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        N = sc.nextInt();
+        M = sc.nextInt();
+        sc.nextLine();
+
+        for(int i=0; i<N; i++) {
+            char[] line = sc.nextLine().toCharArray();
+            for(int j=0; j<M; j++) {
+                mapInfo[i][j] = line[j];
+                parents[area_num(i, j)] = area_num(i, j);
+            }
+        }
+        sc.close();
+
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<M; j++) {
+                char arrow = mapInfo[i][j];
+                int current_area = area_num(i, j);
+                int next_area = 0;
+
+                if (arrow == 'U') next_area = area_num(i-1, j);
+                else if (arrow == 'D') next_area = area_num(i+1, j);
+                else if (arrow == 'L') next_area = area_num(i, j-1);
+                else if (arrow == 'R') next_area = area_num(i, j+1);
+
+                union(current_area, next_area);
+            }
+        }
+
+        int result = 0;
+        for(int i=0; i<N*M; i++) {
+            if(parents[i] == i) result++;
+        }
+
+        System.out.println(result);
+    }
+}

code_study/Baekjoon/ts/17103.ts

@@ -0,0 +1,26 @@
+export {};
+const maxNum = 1000000;
+const input = require("fs").readFileSync(0).toString().trim().split('\n').map(Number);
+const T: number = input[0];
+
+let isPrime: boolean[] = Array.from({length: maxNum+1}, (_, i) => i>=2 ? true: false);
+
+for(let n=2; n*n<=maxNum; n++) {
+    if(isPrime[n]) {
+        for(let i=n*n; i<=maxNum; i+=n) isPrime[i] = false;
+    }
+}
+
+let result: number[] = [];
+for(let t=1; t<=T; t++) {
+    const num: number = input[t];
+    let count: number = 0;
+
+    for(let i=2; i<=num/2; i++) {
+        if(isPrime[num-i] && isPrime[i]) count++;
+    }
+
+    result.push(count);
+}
+
+console.log(result.join('\n'));