Merge pull request #127 from LEEHYUNDONG/main

220810/이현동

Author: LEEHYUNDONG

[Week17 - NumberTheory&Prime]/이현동/1978

@@ -0,0 +1,43 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int N;
+int arr[101];
+int tmp[1001];
+
+void isPrime(int x)
+{
+    for (int i = 0; i <= x;i++)
+        tmp[i] = i;
+    tmp[1] = 0;
+
+    for (int i = 2; i <= x; i++)
+    {
+        if(tmp[i] == 0)
+            continue;
+        for (int j = i+i; j <= x; j += i)
+            tmp[j] = 0;
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    int cnt = 0;
+
+    cin >> N;
+    for (int i = 0; i < N;i++)
+        cin >> arr[i];
+
+    isPrime(1000);
+
+    for (int i = 0; i < N;i++){
+        if (tmp[arr[i]] != 0)    
+            cnt++;
+        
+    }
+    cout << cnt;
+    return 0;
+}

[Week17 - NumberTheory&Prime]/이현동/1978.cpp

@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int N;
+int arr[10001];
+int tmp[10001];
+/*
+8 = 1 7, 2 6, 3 5, 4 4,
+*/
+
+void isPrime(int x)
+{
+    for (int i = 0; i <= x;i++)
+        tmp[i] = i;
+    tmp[1] = 0;
+
+    for (int i = 2; i <= x; i++)
+    {
+        if(tmp[i] == 0)
+            continue;
+        for (int j = i+i; j <= x; j += i)
+            tmp[j] = 0;
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cin >> N;
+    for (int i = 0; i < N;i++)
+        cin >> arr[i];
+    
+    //make prime Number set
+    isPrime(10000);
+
+    for (int i = 0; i < N; i++)
+    {
+        int a, b;
+        for (int j = 2; j <= arr[i] / 2; j++)
+        {
+            if(tmp[arr[i]-j] != 0 && tmp[j] != 0){
+                b = arr[i] - j;
+                a = j;
+            }
+        }
+        cout << a << ' ' << b << '\n';
+    }
+        return 0;
+}