ashelly · February 1, 2019 04:59 · Feb 1, 2019
diff --git a/permutation.c b/permutation.c
@@ -0,0 +1,18 @@
+static inline void Exchange(int* data, int a, int b) {
+  int temp = data[a];
+  data[a]=data[b];
+  data[b]=temp;
+}
+
+//generates all permutations of initially sorted array `a` with `n` elements
+//returns 0 when no more permutations exist
+int genPermutation(int a[], int n) 
+{
+  int l,j;
+  for (j = --n; j > 0 && a[j-1] >= a[j]; --j) { ; }
+  if (j == 0) return 0; 
+  for (l = n; a[j-1] >= a[l]; --l) { ; }
+  Exchange(a, j-1, l);
+  while (j < n) { Exchange(a, j++ ,n--); }
+  return 1;
+}