Add ternary_search

Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>

graph/bfs.cpp

 /**
  * Breadth First Search - BFS
+ *
  * Complexity (Time): O(|V| + |E|)
  * Complexity (Space): O(|V| + |E|)
  */

graph/dfs.cpp

 /**
  * Depth First Search - DFS
+ *
  * Complexity (Time): O(|V| + |E|)
  * Complexity (Space): O(|V| + |E|)
  */

graph/dijkstra.cpp

 /**
  * Dijkstra
+ *
  * Complexity (Time): O(|E| + |V| log |V|)
  * Complexity (Space): O(|E| + |V|)
  */

paradigm/ternary_search.cpp

+/** 
+ * Ternary Search
+ *
+ * Complexity (Time): O(log n)
+ * Complexity (Space): O(1)
+ */
+
+#define EPS 1e-6 
+
+// Unimodal function
+double f(double x) {
+  return x * x;
+}
+
+// Execute ternary search to find maximum or minimum between l and r
+double ternary_search(double l, double r) {
+  double rt, lt;
+
+  for (int i = 0; i < 500; ++i) {
+    if (fabs(r - l) < EPS)
+      return (l + r) / 2.0;
+
+    lt = l + (r - l) / 3.0;
+    rt = r - (r - l) / 3.0;
+
+    // < | minimum of f
+    // > | maximum of f
+    if (f(lt) < f(rt))
+      l = lt;
+    else
+      r = rt;
+  }
+
+  return (l + r) / 2.0;
+}

structure/bit.cpp

 /**
  * Binary Indexed Tree - BIT 
+ *
  * Complexity (Time):
  *   Update -> O(log n)
  *   Query  -> O(log n)
- *
  * Complexity (Space): O(n)
  */
 

structure/bit2d.cpp

 /** 
  * Binary Indexed Tree 2D - BIT2D
+ *
  * Complexity (Time):
  *   Update -> O(log^2 n)
  *   Query  -> O(log^2 n)
- *
  * Complexity (Space): O(n^2)
  */
 

structure/bitmask.cpp

 /**
  * Bitmask 
+ *
  * Complexity (Time): O(1)
  * Complexity (Space): O(1)
  */

structure/segment_tree.cpp

 /**
  * Segment Tree
+ *
  * Complexity (Time):
- *     Build  -> O(n log n)
- *     Update -> O(log n)
- *     Query  -> O(log n)
+ *   Build  -> O(n log n)
+ *   Update -> O(log n)
+ *   Query  -> O(log n)
  * Complexity (Space): O(n)
  */