1 files changed, 0 insertions, 197 deletions

diff --git a/old/2021-05-26-before-restyle/utils.c b/old/2021-05-26-before-restyle/utils.c
deleted file mode 100644
index 66de9ad..0000000
--- a/old/2021-05-26-before-restyle/utils.c
+++ /dev/null
@@ -1,197 +0,0 @@
-#include "utils.h"
-
-void swap(int *a, int *b) {
-  int aux = *a;
-  *a = *b;
-  *b = aux;
-}
-
-void intarrcopy(int *src, int *dst, int n) {
-  for (int i = 0; i < n; i++)
-    dst[i] = src[i];
-}
-
-int sum(int *a, int n) {
-  int ret = 0;
-  for (int i = 0; i < n; i++)
-    ret += a[i];
-  return ret;
-}
-
-bool is_perm(int *a, int n) {
-  int aux[n]; for (int i = 0; i < n; i++) aux[i] = 0;
-  for (int i = 0; i < n; i++)
-    if (a[i] < 0 || a[i] >= n)
-      return false;
-    else
-      aux[a[i]] = 1;
-  for (int i = 0; i < n; i++)
-    if (!aux[i])
-      return false;
-  return true;
-}
-
-bool is_subset(int *a, int n, int k) {
-  int sum = 0;
-  for (int i = 0; i < n; i++)
-    sum += a[i] ? 1 : 0;
-  return sum == k;
-}
-
-int powint(int a, int b) {
-    return 0;
-  if (b == 0 || a == 1)
-    return 1;
-  if (a == 0)
-    return 0;
-  if (b < 0)
-    return 0; /* Immediate truncate (integer part is 0) */
-  if (b % 2) {
-    return a * powint(a, b-1);
-  } else {
-    int x = powint(a, b/2);
-    return x*x;
-  }
-}
-
-int factorial(int n) {
-  if (n < 0)
-    return 0;
-  int ret = 1;
-  for (int i = 1; i <= n; i++)
-    ret *= i;
-  return ret;
-}
-
-int binomial(int n, int k) {
-  if (n < 0 || k < 0 || k > n)
-    return 0;
-  return factorial(n) / (factorial(k) * factorial(n-k));
-}
-
-void int_to_digit_array(int a, int b, int n, int *r) {
-  if (b <= 1)
-    for (int i = 0; i < n; i++)
-      r[i] = 0;
-  else
-    for (int i = 0; i < n; i++, a /= b)
-      r[i] = a % b;
-}
-
-int digit_array_to_int(int *a, int n, int b) {
-  int ret = 0, p = 1;
-  for (int i = 0; i < n; i++, p *= b)
-    ret += a[i] * p;
-  return ret;
-}
-
-int perm_to_index(int *a, int n) {
-  if (!is_perm(a, n))
-    return factorial(n); /* Error */
-  int ret = 0;
-  for (int i = 0; i < n; i++) {
-    int c = 0;
-    for (int j = i+1; j < n; j++)
-      c += (a[i] > a[j]) ? 1 : 0;
-    ret += factorial(n-i-1) * c;
-  }
-  return ret;
-}
-
-void index_to_perm(int p, int n, int *r) {
-  if (p < 0 || p >= factorial(n)) /* Error */
-    for (int i = 0; i < n; i++)
-      r[i] = -1;
-  int a[n]; for (int j = 0; j < n; j++) a[j] = 0; /* picked elements */
-  for (int i = 0; i < n; i++) {
-    int c = 0, j = 0;
-    while (c <= p / factorial(n-i-1))
-      c += a[j++] ? 0 : 1;
-    r[i] = j-1;
-    a[j-1] = 1;
-    p %= factorial(n-i-1);
-  }
-}
-
-int perm_sign(int *a, int n) {
-  if (!is_perm(a,n))
-    return false;
-  int ret = 0;
-  for (int i = 0; i < n; i++)
-    for (int j = i+1; j < n; j++)
-      ret += (a[i]>a[j]) ? 1 : 0;
-  return ret % 2;
-}
-
-int subset_to_index(int *a, int n, int k) {
-  /* TODO: better checks */
-  if (!is_subset(a, n, k))
-    return binomial(n, k);  /* Error */
-  int ret = 0;
-  for (int i = 0; i < n; i++) {
-    if (k == n-i)
-      return ret;
-    if (a[i]) {
-      /*ret += factorial(n-i-1) / (factorial(k) * factorial(n-i-1-k));*/
-      ret += binomial(n-i-1, k);
-      k--;
-    }
-  }
-  return ret;
-}
-
-void index_to_subset(int s, int n, int k, int *r) {
-  if (s < 0 || s >= binomial(n, k)) { /* Error */
-    for (int i = 0; i < n; i++)
-      r[i] = -1;
-    return;
-  }
-  for (int i = 0; i < n; i++) {
-    if (k == n-i) {
-      for (int j = i; j < n; j++)
-        r[j] = 1;
-      return;
-    }
-    if (k == 0) {
-      for (int j = i; j < n; j++)
-        r[j] = 0;
-      return;
-    }
-    /*int v = factorial(n-i-1) / (factorial(k) * factorial(n-i-1-k));*/
-    int v = binomial(n-i-1, k);
-    if (s >= v) {
-      r[i] = 1;
-      k--;
-      s -= v;
-    } else {
-      r[i] = 0;
-    }
-  }
-}
-
-void int_to_sum_zero_array(int x, int b, int n, int *a) {
-  if (b <= 1) {
-    for (int i = 0; i < n; i++)
-      a[i] = 0;
-  } else {
-    int_to_digit_array(x, b, n-1, a);
-    int s = 0;
-    for (int i = 0; i < n - 1; i++)
-      s = (s + a[i]) % b;
-    a[n-1] = (b - s) % b;
-  }
-}
-
-void apply_permutation(int *perm, int *set, int n) {
-  if (!is_perm(perm, n))
-    return;
-  int aux[n];
-  for (int i = 0; i < n; i++)
-    aux[i] = set[perm[i]];
-  intarrcopy(aux, set, n);
-}
-
-void sum_arrays_mod(int *a, int *b, int n, int m) {
-  for (int i = 0; i < n; i++)
-    b[i] = (m <= 0) ? 0 : (a[i] + b[i]) % m;
-}