lcm

1 files changed, 48 insertions, 0 deletions

diff --git a/src/math.c b/src/math.c
new file mode 100644
index 0000000..3e36e3b
--- /dev/null
+++ b/src/math.c
@@ -0,0 +1,48 @@
+/*local function gcd(a,b)
+  if b == 0 then return a end
+  return gcd(b, math.fmod(a, b))
+end
+
+local function lcm(a)
+  local out = a[1]
+
+  for i=2,#a do
+    out = ((a[i] * out)) / (gcd(a[i], out))
+  end
+  return out
+end
+*/
+#include "math.h"
+#include "stdint.h"
+#include <stdlib.h>
+
+uint64_t gcd(uint64_t a, uint64_t b){
+  if(b == 0) return a;
+  return gcd(b, a % b);
+}
+
+uint64_t lcm(uint64_t* a, size_t len){
+  uint64_t out = a[0];
+  
+  for(size_t i = 1; i != len; i++){
+    out = (a[i] * out) / gcd(a[i], out);
+  }
+  return out;
+}
+
+int l_lcm(lua_State* L){
+  luaL_checktype(L, 1, LUA_TTABLE);
+  size_t len = lua_objlen(L,1); 
+  uint64_t* nums = malloc(sizeof * nums * len);
+  for(size_t i = 0; i <= len-1; i++){
+
+    lua_pushinteger(L,i+1);
+    lua_gettable(L,1);
+       
+    nums[i] = luaL_checknumber(L, -1);
+    lua_pop(L,1);
+  }
+  lua_pushnumber(L, lcm(nums, len));
+  free(nums);
+  return 1;
+}