Envío 1964

Código

#include <iostream>
#include <vector>
#include <stack>

using namespace std;

void print(const vector<int> &a) {
  for (int i = 0; i < a.size(); i++) {
    cout << a[i] << " ";
  }
  cout << endl;
}

vector<int> solve(const vector<int> &a) {
  stack<int> pendingIndexes;
  vector<int> solution(a.size());
  // push the first index to the pending stack
  pendingIndexes.push(0);
  for (int i = 1; i < a.size(); i++) {
	 if(!pendingIndexes.empty()) {
		int topIndex = pendingIndexes.top();
		int top = a[topIndex];
		int current = a[i];
		// If the top of the stack < current element :
		// current element is NGE for all element on stack < current
		while (current > top and !pendingIndexes.empty()) {
		  int topIndex = pendingIndexes.top();
		  solution[topIndex] = current;
		  pendingIndexes.pop();
		  if (!pendingIndexes.empty()) {
			 topIndex = pendingIndexes.top();
		  }
		  top = a[topIndex];
		}
	 }
	 pendingIndexes.push(i);
  }
  // All the remaining elements in stack have no NGE
  while (!pendingIndexes.empty()) {
	 int topIndex = pendingIndexes.top();
	 solution[topIndex] = -1;
	 pendingIndexes.pop();
  }
  return solution;
}

int main() {
  int C;
  cin >> C;
  for (int i = 0; i < C; i++) {
	 int N;
	 cin >> N;
	 vector<int> a(N);
	 for (int i = 0; i < N; i++) {
		cin >> a[i]; 
	 }
	 vector<int> s = solve(a);
	 cout << "Case #" << (i+1) << ": ";
	 print(s);
  }
  return 0;
}