1def calculate_capital_gain_loss(stocks):
2    gains = {}
3
4    for stock in stocks:
5        name = stock['stock_name']
6        operation = stock['operation']
7        price = stock['price']
8
9        if operation == 'Buy':
10            if name not in gains:
11                gains[name] = {'prices': [], 'net': 0}
12            gains[name]['prices'].append(price)
13        elif operation == 'Sell':
14            buy_price = gains[name]['prices'].pop(0)
15            gain_loss = price - buy_price
16            gains[name]['net'] += gain_loss
17
18    result = [{'stock_name': k, 'capital_gain_loss': v['net']} for k, v in gains.items()]
19    return result

1#include <iostream>
2#include <vector>
3#include <string>
#include <unordered_map>
#include <deque>
#include <algorithm>

struct Stock {
    std::string stock_name;
    std::string operation;
    int operation_day;
    int price;
};

bool compare(Stock a, Stock b) {
    return a.operation_day < b.operation_day;
}

std::vector<std::pair<std::string, int>> calculateCapitalGainLoss(std::vector<Stock> stocks) {
    std::unordered_map<std::string, std::deque<int>> buyPrices;
    std::unordered_map<std::string, int> netGains;

    std::sort(stocks.begin(), stocks.end(), compare);

    for (auto& stock : stocks) {
        if (stock.operation == "Buy") {
            buyPrices[stock.stock_name].push_back(stock.price);
        } else if (stock.operation == "Sell") {
            int buyPrice = buyPrices[stock.stock_name].front();
            buyPrices[stock.stock_name].pop_front();
            int gainLoss = stock.price - buyPrice;
            netGains[stock.stock_name] += gainLoss;
        }
    }

    std::vector<std::pair<std::string, int>> result;
    for (const auto& pair : netGains) {
        result.push_back(pair);
    }

    return result;
}