'commit'

TangDou/LuoGuBook/P1304_1.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+//欧拉筛
+const int N = 1e5 + 10;
+int primes[N], cnt;     // primes[]存储所有素数
+bool st[N];             // st[x]存储x是否被筛掉
+void get_primes(int n) {
+    for (int i = 2; i <= n; i++) {
+        if (!st[i]) primes[cnt++] = i;
+        for (int j = 0; primes[j] * i <= n; j++) {
+            st[primes[j] * i] = true;
+            if (i % primes[j] == 0) break;
+        }
+    }
+}
+
+int n;
+
+int main() {
+    cin >> n;
+    get_primes(n);
+    for (int i = 4; i <= n; i += 2)
+        for (int j = 2; j < i; j++)
+            if (!st[j] && !st[i - j]) {
+                printf("%d=%d+%d\n", i, j, i - j);
+                break;
+            }
+    return 0;
+}