Create Pchelyonok and Segments.cpp

Author: MathProgrammer

2021/Div 2/750/Programs/Pchelyonok and Segments.cpp

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+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+long long get_largest_k(long long n)
+{
+    long long right = n, left = 1;
+
+    while(right - left > 1)
+    {
+        long long mid = (left + right)/2;
+
+        if(mid*1LL*(mid + 1) <= 2*n)
+        {
+            left = mid;
+        }
+        else
+        {
+            right = mid;
+        }
+    }
+
+    return left;
+}
+
+void solve()
+{
+    int no_of_elements;
+    cin >> no_of_elements;
+
+    vector <long long> A(no_of_elements + 5, 0);
+    for(int i = 1; i <= no_of_elements; i++)
+    {
+        cin >> A[i];
+    }
+
+    vector <long long> sum_from(no_of_elements + 5, 0);
+    for(int i = no_of_elements; i >= 1; i--)
+    {
+        sum_from[i] = A[i] + sum_from[i + 1];
+    }
+
+    long long max_k = get_largest_k(no_of_elements);
+
+    vector <vector <long long> > max_segment_sum(no_of_elements + 5, vector <long long> (max_k + 1));
+    for(int i = no_of_elements; i >= 1; i--)
+    {
+        for(int segment_size = 1; segment_size <= max_k; segment_size++)
+        {
+            max_segment_sum[i][segment_size] = max_segment_sum[i + 1][segment_size];
+
+            if(i + segment_size - 1 > no_of_elements)
+            {
+                continue;
+            }
+
+            long long sum_here = sum_from[i] - sum_from[i + segment_size];
+
+            if(segment_size == 1 || sum_here < max_segment_sum[i + segment_size][segment_size - 1])
+            {
+                max_segment_sum[i][segment_size] = max(max_segment_sum[i][segment_size], sum_here);
+            }
+        }
+    }
+
+    int answer = 0;
+    for(int segment_size = max_k; segment_size >= 1; segment_size--)
+    {
+        if(max_segment_sum[1][segment_size] > 0)
+        {
+            answer = segment_size;
+            break;
+        }
+    }
+
+    cout << answer << "\n";
+}
+
+int main()
+{
+    int no_of_test_cases;
+    cin >> no_of_test_cases;
+
+    while(no_of_test_cases--)
+        solve();
+
+    return 0;
+}