// External-compilation version of r3cts table layout solver header.
// Don’t use this.  Use r3cts.h.

// An assertion that position[end] ≥ position[start] + width.
// Can only be added to one r3_system at a time.
typedef struct r3_constraint {
  // Requirement: start < end.
  int start, end, width;
  // prev is a link to previous constraint with same `end`.
  struct r3_constraint *prev;
} r3_constraint;

typedef struct {
  int n;          // maximum number of values to compute, at least 1
  int m;          // actual number of values computed; initialize to 0
  r3_constraint **latest; // points to a null-initialized array of size n
} r3_system;

// Returns NULL on success, error message string on failure (n too small)
const char *r3_add_constraint(r3_system *r3, r3_constraint *c);

// Places r3->m solver results in position[].
void r3_solve_system(r3_system *r3, int position[]);