Finished 071 by using fraction arithmetics

projecteuler/071/main.cpp

@@ -0,0 +1,42 @@
+/*
+
+Ordered Fractions
+
+Consider the fraction, n/d, where n and d are positive integers. If n<d and HCF(n,d)=1, it is called a reduced proper fraction.
+
+If we list the set of reduced proper fractions for d ≤ 8 in ascending order of size, we get:
+
+1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, 1/2, 4/7, 3/5, 5/8, 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 7/8
+
+It can be seen that 2/5 is the fraction immediately to the left of 3/7.
+
+By listing the set of reduced proper fractions for d ≤ 1,000,000 in ascending order of size, find the numerator of the fraction immediately to the left of 3/7.
+
+*/
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+const int MAX = 1000000;
+
+int main(){
+
+    cout << "Hello this is Patrick" << endl;
+    auto start = chrono::high_resolution_clock::now();
+
+    long a = 3, b = 7, r = 0, s = 1;
+    for(int q = MAX; q > 2; q--){
+        long p = (a * q - 1) / b;
+        if(p * s > r * q){
+            s = q;
+            r = p;
+        }
+    }
+
+    cout << r << " / " << s << endl; 
+
+    auto duration = chrono::duration_cast<chrono::milliseconds>(chrono::high_resolution_clock::now() - start);
+    cout << (float)duration.count()/1000 << endl;
+    return 0;
+}