PE 77, used dynamic programming

projecteuler/077/main.cpp

@@ -0,0 +1,60 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int MAXN = 1000;
+
+vector<int> genPrimes(int n){
+    vector<bool> primeBinary(n+1, true);
+
+    for(int i = 2; i <= n; ++i){
+        if(primeBinary[i]){
+            for(int j = 2 * i; j <= n; j += i){
+                primeBinary[j] = false;
+            }
+        }
+    }
+
+    vector<int> result;
+
+    for(int i = 2; i <= n; ++i){
+        if(primeBinary[i]){
+            result.push_back(i);
+        }
+    }
+
+    return result;
+}
+
+int main(){
+
+    cout << "Hello this is Patrick" << endl;
+    auto start = chrono::high_resolution_clock::now();
+
+    auto primes = genPrimes(MAXN);
+    set<int> primeSet(primes.begin(), primes.end());
+
+    vector<unsigned long long> solutions(MAXN + 1, 0);
+    solutions[0] = 1;
+
+    for(int i = 2; i <= MAXN; ++i){
+        if(primeSet.count(i)){
+            for(int pos = 0; pos <= MAXN - i; ++pos){
+                solutions[pos + i] += solutions[pos];
+            }
+        }
+    }
+
+    for(int i = 0; i < solutions.size(); ++i){
+        // cout << solutions[i] << " ";
+        if(solutions[i] > 5000){
+            cout << i << endl;
+            break;
+        }
+    }
+
+
+    auto duration = chrono::duration_cast<chrono::milliseconds>(chrono::high_resolution_clock::now() - start);
+    cout << (float)duration.count()/1000 << endl;
+    return 0;
+}