diff options
Diffstat (limited to 'array.c')
-rw-r--r-- | array.c | 27 |
1 files changed, 4 insertions, 23 deletions
@@ -3958,26 +3958,6 @@ rb_ary_permutation(int argc, VALUE *argv, VALUE ary) return ary; } -static long -combi_len(long n, long k) -{ - long i, val = 1; - - if (k*2 > n) k = n-k; - if (k == 0) return 1; - if (k < 0) return 0; - val = 1; - for (i=1; i <= k; i++,n--) { - long m = val; - val *= n; - if (val < m) { - rb_raise(rb_eRangeError, "too big for combination"); - } - val /= i; - } - return val; -} - /* * call-seq: * ary.combination(n) { |c| block } -> ary @@ -4024,14 +4004,13 @@ rb_ary_combination(VALUE ary, VALUE num) else { volatile VALUE t0 = tmpbuf(n+1, sizeof(long)); long *stack = (long*)RSTRING_PTR(t0); - long nlen = combi_len(len, n); volatile VALUE cc = tmpary(n); VALUE *chosen = RARRAY_PTR(cc); long lev = 0; MEMZERO(stack, long, n); stack[0] = -1; - for (i = 0; i < nlen; i++) { + for (;;) { chosen[lev] = RARRAY_PTR(ary)[stack[lev+1]]; for (lev++; lev < n; lev++) { chosen[lev] = RARRAY_PTR(ary)[stack[lev+1] = stack[lev]+1]; @@ -4041,9 +4020,11 @@ rb_ary_combination(VALUE ary, VALUE num) rb_raise(rb_eRuntimeError, "combination reentered"); } do { + if (lev == 0) goto done; stack[lev--]++; - } while (lev && (stack[lev+1]+n == len+lev+1)); + } while (stack[lev+1]+n == len+lev+1); } + done: tmpbuf_discard(t0); tmpary_discard(cc); } |