Create Or Plus Max.cpp

Author: MathProgrammer

Contests/AtCoder Regular Contest 100/Programs/Or Plus Max.cpp

@@ -0,0 +1,75 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+int is_bit_set(int n, int bit)
+{
+ return ( ( n & (1 << bit) ) != 0 );
+}
+
+void update(int n, int &largest, int &second_largest, vector <int> &A)
+{
+ //cout << "Updating " << A[n] << "\n";
+ if(n == largest || n == second_largest)
+ { //cout << "Return";
+ return;
+ }
+
+ if(largest == -1 || A[n] > A[largest])
+ {
+ second_largest = largest;
+ largest = n;
+ }
+ else if(second_largest == -1 || A[n] >= A[second_largest])
+ {
+ second_largest = n;
+ }
+
+ //cout << "Largest = " << A[largest] << " " << A[second_largest] << "\n";
+}
+
+int main()
+{
+ int no_of_elements;
+ cin >> no_of_elements;
+
+ int max_mask = 1 << no_of_elements;
+ vector <int> A(max_mask + 1);
+ for(int i = 0; i < max_mask; i++)
+ {
+ cin >> A[i];
+ }
+
+ vector <int> largest(max_mask, -1), second_largest(max_mask, -1), sum(max_mask);
+ largest[0] = second_largest[0] = 0;
+ for(int m = 1; m < max_mask; m++)
+ {
+ //cout << "At " << m << " ";
+ update(0, largest[m], second_largest[m], A);
+ update(m, largest[m], second_largest[m], A);
+
+ for(int bit = 0; bit < no_of_elements; bit++)
+ {
+ if(is_bit_set(m, bit))
+ {
+ int submask_without_this_bit = m^(1 << bit);
+ //cout << " At old " << submask_without_this_bit << "\n";
+ update(largest[submask_without_this_bit], largest[m], second_largest[m], A);
+ update(second_largest[submask_without_this_bit], largest[m], second_largest[m], A);
+ }
+ }
+ }
+
+ for(int m = 1; m < max_mask; m++)
+ {
+ sum[m] = max(sum[m - 1], A[largest[m]] + A[second_largest[m]]);
+ }
+
+ for(int m = 1; m < max_mask; m++)
+ {
+ cout << sum[m] << "\n";
+ }
+
+ return 0;
+}