'commit'

TangDou/AcWing/Math/201_1.cpp

@@ -0,0 +1,44 @@
+#include <cstdio>
+#include <cstring>
+#include <iostream>
+using namespace std;
+
+//快读
+int read() {
+    int x = 0, f = 1;
+    char ch = getchar();
+    while (ch < '0' || ch > '9') {
+        if (ch == '-') f = -1;
+        ch = getchar();
+    }
+    while (ch >= '0' && ch <= '9') {
+        x = (x << 3) + (x << 1) + (ch ^ 48);
+        ch = getchar();
+    }
+    return x * f;
+}
+
+const int N = 1010;
+
+// 功能：欧拉函数
+int get_euler(int x) {
+    int res = x;
+    for (int i = 2; i <= x / i; i++)
+        if (x % i == 0) {
+            res = res / i * (i - 1);
+            while (x % i == 0) x /= i;
+        }
+    if (x > 1) res = res / x * (x - 1);
+    return res;
+}
+
+int main() {
+    int n, m = read();
+    for (int i = 1; i <= m; i++) {
+        n = read();
+        int res = 1;                                    // x=y 记1个
+        for (int j = 1; j <= n; j++) res += get_euler(j) * 2; //叠加两倍的欧拉函数值
+        printf("%d %d %d\n", i, n, res);
+    }
+    return 0;
+}