Initial data commit

Task/Square-form-factorization/C/square-form-factorization-2.c

@@ -0,0 +1,139 @@
+//SquFoF: minimalistic version without queue.
+//Classical heuristic. Tested: tcc 0.9.27
+#include <math.h>
+#include <stdio.h>
+
+//input maximum
+#define MxN ((unsigned long long) 1 << 62)
+
+//reduce indefinite form
+#define rho(a, b, c) {        \
+  t = c; c = a; a = t; t = b; \
+   q = (rN + b) / a;          \
+   b = q * a - b;             \
+   c += q * (t - b); }
+
+//initialize
+#define rhoin(a, b, c) {      \
+   rho(a, b, c)  h = b;       \
+   c = (mN - h * h) / a; }
+
+#define gcd(a, b) while (b) { \
+   t = a % b; a = b; b = t; }
+
+//multipliers
+const unsigned long m[] = {1, 3, 5, 7, 11, 0};
+
+//square form factorization
+unsigned long squfof( unsigned long long N ) {
+unsigned long a, b, c, u, v, w, rN, q, t, r;
+unsigned long long mN, h;
+int i, ix, k = 0;
+
+   if ((N & 1)==0) return 2;
+
+   h = floor(sqrt(N)+ 0.5);
+   if (h * h == N) return h;
+
+   while (m[k]) {
+      if (k && N % m[k]==0) return m[k];
+      //check overflow m * N
+      if (N > MxN / m[k]) break;
+      mN = N * m[k++];
+
+      r = floor(sqrt(mN));
+      h = r; //float64 fix
+      if (h * h > mN) r -= 1;
+      rN = r;
+
+      //principal form
+      b = r; c = 1;
+      rhoin(a, b, c)
+
+      //iteration bound
+      ix = floor(sqrt(2*r)) * 4;
+
+      //search principal cycle
+      for (i = 2; i < ix; i += 2) {
+         rho(a, b, c)
+         //even step
+
+         r = floor(sqrt(c)+ 0.5);
+         if (r * r == c) {
+            //square form found
+
+            //inverse square root
+            v = -b; w = r;
+            rhoin(u, v, w)
+
+            //search ambiguous cycle
+            do { r = v;
+              rho(u, v, w)
+            } while (v != r);
+            //symmetry point
+
+            h = N; gcd(h, u)
+            if (h != 1) return h;
+         }
+         rho(a, b, c)
+         //odd step
+      }
+   }
+   return 1;
+}
+
+void main(void) {
+const unsigned long long data[] = {
+   2501,
+   12851,
+   13289,
+   75301,
+   120787,
+   967009,
+   997417,
+   7091569,
+
+   5214317,
+   20834839,
+   23515517,
+   33409583,
+   44524219,
+
+   13290059,
+   223553581,
+   2027651281,
+   11111111111,
+   100895598169,
+   1002742628021,
+   60012462237239,
+   287129523414791,
+   9007199254740931,
+   11111111111111111,
+   314159265358979323,
+   384307168202281507,
+   419244183493398773,
+   658812288346769681,
+   922337203685477563,
+   1000000000000000127,
+   1152921505680588799,
+   1537228672809128917,
+   4611686018427387877,
+   0};
+
+   unsigned long long N, f;
+   int i = 0;
+
+   while (1) {
+      N = data[i++];
+      //scanf("%llu", &N);
+      if (N < 2) break;
+
+      printf("N = %llu\n", N);
+
+      f = squfof(N);
+      if (N % f) f = 1;
+
+      if (f == 1) printf("fail\n\n");
+      else printf("f = %llu  N/f = %llu\n\n", f, N/f);
+   }
+}