soldiers_pb

#include <bits/stdc++.h>
using namespace std;

void solveSoldiersRow(vector<int> &heights) {
    stack<int> soldiersStack;
    for (int index = 0; index < (int)heights.size(); ++index) {
        while (!soldiersStack.empty() && soldiersStack.top() <= heights[index]) {
            soldiersStack.pop();
        }
        if (soldiersStack.empty()) {
            // This soldier has clear visibility
            cout << -1 << "\n";
        } else {
            // Found the corresponding pair
            cout << soldiersStack.top() << "\n";
        }
        soldiersStack.push(heights[index]);
    }
}

int main()
{
    vector <int> v{5,3,1,4,9,2,7,5,2,4};
    solveSoldiersRow(v);
    return 0;
}