bzoj 1041

OnlineJudges/lydsy/1041.cpp

@@ -0,0 +1,30 @@
+#include <cstdio>
+#include <cmath>
+inline unsigned gcd(unsigned x, unsigned y)
+{
+    unsigned t;
+    while (y) t = x % y, x = y, y = t;
+    return x;
+}
+unsigned calc(unsigned x)
+{
+    unsigned ret = 0;
+    for (unsigned i = 1, j; i * i <= x; i++)
+    {
+        j = unsigned(sqrt(x - i * i) + 0.5);
+        if (i >= j) break;
+        if (i * i + j * j == x && gcd(i, j) == 1) ret++;
+    }
+    return ret;
+}
+int main()
+{
+    unsigned n, ans = 1;
+    scanf("%u", &n);
+    n <<= 1;
+    for (unsigned i = 1; i * i <= n; i++)
+        if (n % i == 0)
+            ans += calc(n / i) + (i * i == n ? 0 : calc(i));
+    printf("%u", ans << 2);
+    return 0;
+}