20250917 baekjoon

code_study/Baekjoon/ts/4948.ts

@@ -0,0 +1,24 @@
+export {};
+
+const maxNum: number = 123456*2;
+let isPrime: boolean[] = Array.from({length: maxNum + 1}, (_, i) => i>1 ? true : false);
+
+for(let i=2; i*i <= maxNum; i++) {
+    if (isPrime[i]) {
+        let num: number = i*i;
+        while(num <= maxNum) {
+            isPrime[num] = false;
+            num += i;
+        }
+    }
+}
+
+const input: number[] = require("fs").readFileSync(0).toString().trim().split('\n').map(Number);
+for(let n of input) {
+    if (n===0) break;
+    let count: number = 0;
+    for(let i=n+1; i<=2*n; i++) {
+        if (isPrime[i]) count++;
+    }
+    console.log(count);
+}