Merge branch 'master' into doe

1 files changed, 77 insertions, 0 deletions

diff --git a/test-chill/unit-tests/cprog/MergeSorter.cc b/test-chill/unit-tests/cprog/MergeSorter.cc
new file mode 100644
index 0000000..6e747a3
--- /dev/null
+++ b/test-chill/unit-tests/cprog/MergeSorter.cc
@@ -0,0 +1,77 @@
+#include "MergeSorter.h"
+
+/* Python
+def msort(lst, start, end, pindent = 0):
+    if start == end:
+        return
+    center = start + ((end - start) // 2)
+    print(' '*pindent + "SPLIT {}|{}".format(lst[start:center+1], lst[center+1:end+1]))
+    msort(lst, start, center, pindent+1)
+    msort(lst, center+1, end, pindent+1)
+    left = list(lst[start:center+1])
+    right = list(lst[center+1:end+1])
+    print(' '*pindent + "MERGE {}|{}".format(lst[start:center+1], lst[center+1:end+1]))
+    i,j = 0, 0
+    for k in range(start, end+1):
+        if i >= len(left):
+            lst[k] = right[j]
+            j += 1
+            print(' '*(pindent+1) + 'pull j: {} {} {}'.format(lst[start:k+1], left[i:], right[j:]))
+        elif j >= len(right):
+            lst[k] = left[i]
+            i += 1
+            print(' '*(pindent+1) + 'pull i: {} {} {}'.format(lst[start:k+1], left[i:], right[j:]))
+        elif left[i] > right[j]:
+            lst[k] = right[j]
+            j += 1
+            print(' '*(pindent+1) + 'pull j: {} {} {}'.format(lst[start:k+1], left[i:], right[j:]))
+        else:
+            lst[k] = left[i]
+            i += 1
+            print(' '*(pindent+1) + 'pull i: {} {} {}'.format(lst[start:k+1], left[i:], right[j:]))
+    print(' '*pindent + "-- {}".format(lst[start:end+1]))
+        
+
+if __name__ == '__main__':
+    import random as r
+    x = [int(r.random()*12) for i in range(7)]
+    print(x)
+    msort(x, 0, len(x)-1)
+    print(x)
+*/
+
+static void mergesort(std::vector<int>& lst, int start, int end) {
+    if(start == end) return;
+    int center = start + (end-start)/2;
+    mergesort(lst, start, center);
+    mergesort(lst, center+1, end);
+    std::vector<int> left = std::vector<int>(lst.begin()+start, lst.begin()+(center+1));
+    std::vector<int> right = std::vector<int>(lst.begin()+(center+1),lst.begin()+(end+1));
+    int i = 0;
+    int j = 0;
+    for(int k = start; k < (end+1); k++) {
+        if (i >= left.size()) {
+            lst[k] = right[j++];
+        }
+        else if(j >= right.size()) {
+            lst[k] = left[i++];
+        }
+        else if(left[i] > right[j]) {
+            lst[k] = right[j++];
+        }
+        else {
+            lst[k] = left[i++];
+        }
+    }
+}
+
+MergeSorter::MergeSorter() {
+    this->name = std::string("mergesort");
+}
+
+MergeSorter::~MergeSorter() {
+}
+
+void MergeSorter::sort(std::vector<int>& list) const {
+    mergesort(list, 0, list.size()-1);
+}