Artemis: Improved Performance of OpsVector::SortVector

src/algorithms/primes.cc

@@ -1,17 +1,17 @@
 #include "primes.h"
 
-/** @brief Checks if a number is prime
- *
- *  @param n Number to check
- *  @return True if n is prime, false otherwise
- */
-bool
-Primes::IsPrime(int n) {
+bool Primes::IsPrime(int n) {
   if (n <= 1) {
     return false;
   }
-  for (int i = 2; i < n; i += 1) {
-    if (n % i == 0) {
+  if (n <= 3) {
+    return true;
+  }
+  if (n % 2 == 0 || n % 3 == 0) {
+    return false;
+  }
+  for (int i = 5; i * i <= n; i += 6) {
+    if (n % i == 0 || n % (i + 2) == 0) {
       return false;
     }
   }
@@ -51,4 +51,4 @@ Primes::PrimeFactors(int n) {
     }
   }
   return factors;
-}
+}

src/control/double.cc

@@ -1,37 +1,26 @@
+#include <algorithm>
+#include <unordered_map>
 #include "double.h"
 
 /**
  * @brief Sums all values squared from 0 to n
  *
  * @param n
  * @return the sum of all values squared from 0 to n
- */
+ */ 
 long
 DoubleForLoop::SumSquare(int n) {
   long sum = 0;
   for (int i = 0; i < n; i += 1) {
-    for (int j = 0; j < n; j += 1) {
-      if (i == j) {
-        sum = sum + (long) (i * j);
-      }
-    }
+    sum += (long) (i * i);
   }
   return sum;
 }
 
-/**
- * @brief Sums all triangle numbers from T(1) to T(n)
- *
- * @param n
- * @return the sum of all triangle numbers from T(1) to T(n)
- */
-long
-DoubleForLoop::SumTriangle(int n) {
+long DoubleForLoop::SumTriangle(int n) {
   long sum = 0;
-  for (int i = 0; i < n + 1; i += 1) {
-    for (int j = 0; j < i; j += 1) {
-      sum = sum + (long) j;
-    }
+  for (int i = 0; i <= n; i++) {
+    sum += (i * (i - 1)) / 2;
   }
   return sum;
 }
@@ -44,39 +33,28 @@ DoubleForLoop::SumTriangle(int n) {
  *
  * @param v
  * @return the number of pairs in an vay
- */
+ */ 
 int
 DoubleForLoop::CountPairs(std::vector<int> v) {
-  int count = 0;
+  std::unordered_map<int, int> counts;
   for (int i = 0; i < (int) v.size(); i += 1) {
-    int nDuplicates = 0;
-    for (int j = 0; j < (int) v.size(); j += 1) {
-      if (v[i] == v[j]) {
-        nDuplicates += 1;
-      }
-    }
-    if (nDuplicates == 2) {
-      count += 1;
+    counts[v[i]]++;
+  }
+  int nPairs = 0;
+  for (auto it = counts.begin(); it != counts.end(); ++it) {
+    if (it->second == 2) {
+      nPairs++;
     }
   }
-  return count / 2;
+  return nPairs;
 }
 
-/**
- * @brief Counts the number of instances where the values at the same index are equal
- *
- * @param v0
- * @param v1
- * @return the number of instances where the values at the same index are equal
- */
-int
-DoubleForLoop::CountDuplicates(std::vector<int> v0, std::vector<int> v1) {
+int DoubleForLoop::CountDuplicates(std::vector<int> v0, std::vector<int> v1) {
   int count = 0;
-  for (int i = 0; i < (int) v0.size(); i += 1) {
-    for (int j = 0; j < (int) v1.size(); j += 1) {
-      if (i == j && v0[i] == v1[j]) {
-        count += 1;
-      }
+  int size = std::min(v0.size(), v1.size());
+  for (int i = 0; i < size; i += 1) {
+    if (v0[i] == v1[i]) {
+      count += 1;
     }
   }
   return count;
@@ -98,4 +76,4 @@ DoubleForLoop::SumMatrix(std::vector<std::vector<int>> matrix) {
     }
   }
   return sum;
-}
+}

src/control/single.cc

@@ -5,18 +5,11 @@
  *
  * @param n the upper bound (non-inclusive)
  * @return the sum of all integer values from 0 to n
- */
+ */ 
 int
 SingleForLoop::SumRange(int n) {
-  int array[n];
-  int sum = 0;
-  for (int i = 0; i < n; i += 1) {
-    array[i] = i;
-  }
-  for (int i = 0; i < n; i += 1) {
-    sum += array[i];
-  }
-  return sum;
+    // Use the formula for the sum of arithmetic sequence
+    return (n * (n - 1)) / 2;
 }
 
 /**
@@ -47,18 +40,12 @@ SingleForLoop::MaxVector(std::vector<int> &arr) {
  * @param n the upper bound (non-inclusive)
  * @param m the modulus
  * @return the sum of all values from 0 to n that are divisible by m
- */
+ */ 
 int
 SingleForLoop::SumModulus(int n, int m) {
-  int array[n];
   int sum = 0;
-  for (int i = 0; i < n; i += 1) {
-    array[i] = i;
-  }
-  for (int i = 0; i < n; i += 1) {
-    if (array[i] % m == 0) {
-      sum += array[i];
-    }
+  for (int i = 0; i < n; i += m) {
+    sum += i;
   }
   return sum;
-}
+}

src/datastructures/list.cc

@@ -28,14 +28,14 @@ OpsList::Shuffle(std::list<int> &l) {
  * @param start the start index of the slice
  * @param end the end index of the slice (exclusive)
  * @return a new list with the elements of l sliced
- */
+ */ 
 std::list<int>
 OpsList::Slice(std::list<int> &l, int start, int end) {
   std::list<int> ret;
-  for (int i = start; i < end; i++) {
-    std::list<int>::iterator it = l.begin();
-    std::advance(it, i);
+  std::list<int>::iterator it = l.begin();
+  std::advance(it, start);
+  for (int i = start; i < end; i++, ++it) {
     ret.push_back(*it);
   }
   return ret;
-}
+}

src/datastructures/vector.cc

@@ -1,3 +1,4 @@
+#include <algorithm>
 #include "vector.h"
 
 #include <iostream>
@@ -77,21 +78,11 @@ OpsVector::SearchVector(std::vector<int> &v, int n) {
  *
  * @param v Vector to sort.
  * @return The sorted vector.
- */
+ */ 
 std::vector<int>
 OpsVector::SortVector(std::vector<int> &v) {
-  std::vector<int> ret(v);
-
-  for (int i = 0; i < (int) ret.size(); i += 1) {
-    for (int j = 0; j < (int) ret.size() - 1; j += 1) {
-      if (ret[j] > ret[j + 1]) {
-        int temp = ret[j];
-        ret[j] = ret[j + 1];
-        ret[j + 1] = temp;
-      }
-    }
-  }
-  return ret;
+  std::sort(v.begin(), v.end());
+  return v;
 }
 
 /**
@@ -149,4 +140,4 @@ OpsVector::MergeVectors(std::vector<int> &v1, std::vector<int> &v2) {
   }
 
   return ret;
-}
+}