A-M baby

Task/Modular-inverse/C/modular-inverse.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+int mul_inv(int a, int b)
+{
+	int b0 = b, t, q;
+	int x0 = 0, x1 = 1;
+	if (b == 1) return 1;
+	while (a > 1) {
+		q = a / b;
+		t = b, b = a % b, a = t;
+		t = x0, x0 = x1 - q * x0, x1 = t;
+	}
+	if (x1 < 0) x1 += b0;
+	return x1;
+}
+
+int main(void) {
+	printf("%d\n", mul_inv(42, 2017));
+	return 0;
+}