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-rw-r--r--PlaygroundCpp/Sources/Playground.cpp71
1 files changed, 49 insertions, 22 deletions
diff --git a/PlaygroundCpp/Sources/Playground.cpp b/PlaygroundCpp/Sources/Playground.cpp
index 73738d3..47575e1 100644
--- a/PlaygroundCpp/Sources/Playground.cpp
+++ b/PlaygroundCpp/Sources/Playground.cpp
@@ -1,27 +1,54 @@
#include <iostream>
-using std::cin;
-using std::cout;
+#include <cassert>
-int main() {
- int bigger = 0;
- int biggest = 0;
- int n;
- int i;
- cin >> n;
-
- for (int j = 0; j < n; j++) {
- cin >> i;
- if (i > biggest) {
- bigger = biggest;
- biggest = i;
- } else if (i == biggest) {
- bigger = i;
- } else if (i > bigger) {
- bigger = i;
+// The following code calls a naive algorithm for computing a Fibonacci number.
+//
+// What to do:
+// 1. Compile the following code and run it on an input "40" to check that it is slow.
+// You may also want to submit it to the grader to ensure that it gets the "time limit exceeded" message.
+// 2. Implement the fibonacci_fast procedure.
+// 3. Remove the line that prints the result of the naive algorithm, comment the lines reading the input,
+// uncomment the line with a call to test_solution, compile the program, and run it.
+// This will ensure that your efficient algorithm returns the same as the naive one for small values of n.
+// 4. If test_solution() reveals a bug in your implementation, debug it, fix it, and repeat step 3.
+// 5. Remove the call to test_solution, uncomment the line with a call to fibonacci_fast (and the lines reading the input),
+// and submit it to the grader.
+
+int fibonacci_naive(int n) {
+ if (n <= 1)
+ return n;
+
+ return fibonacci_naive(n - 1) + fibonacci_naive(n - 2);
+}
+
+int64_t fibonacci_fast(int n) {
+ // write your code here
+ if (n <= 1)
+ return (int64_t) n;
+ int64_t fibArray [n+1];
+ fibArray[0] = 0;
+ fibArray[1] = 1;
+ for (int j = 2; j < n+1; j++) {
+ fibArray[j] = fibArray[j - 1] + fibArray[j - 2];
}
- }
+ return fibArray[n];
+
+}
+
+void test_solution() {
+ assert(fibonacci_fast(3) == 2);
+ assert(fibonacci_fast(10) == 55);
+ for (int n = 0; n < 20; ++n)
+ assert(fibonacci_fast(n) == fibonacci_naive(n));
+}
- int64_t prod = (int64_t) bigger * (int64_t) biggest;
- cout << prod << "\n";
- return 0;
+int main() {
+ int n = 0;
+ std::cin >> n;
+
+// std::cout << fibonacci_naive(n) << '\n';
+// test_solution();
+ std::cout << fibonacci_fast(n) << '\n';
+ return 0;
}
+