在我的gprof输出中，哪些c++ std函数需要花费相当多的时间？

#include <iostream>
#include <vector>
#include <algorithm>
#include <chrono>

void inefficientFunction() {
    std::vector<int> data;
    for (int i = 0; i < 1000000; ++i) {
        data.push_back(i); // 频繁的内存分配
    }
    std::sort(data.begin(), data.end()); // 排序操作
}

void efficientFunction() {
    std::vector<int> data;
    data.reserve(1000000); // 预分配内存
    for (int i = 0; i < 1000000; ++i) {
        data.push_back(i);
    }
    std::sort(data.begin(), data.end());
}

int main() {
    auto start = std::chrono::high_resolution_clock::now();
    inefficientFunction();
    auto end = std::chrono::high_resolution_clock::now();
    std::chrono::duration<double> elapsed = end - start;
    std::cout << "Inefficient function took: " << elapsed.count() << " s\n";

    start = std::chrono::high_resolution_clock::now();
    efficientFunction();
    end = std::chrono::high_resolution_clock::now();
    elapsed = end - start;
    std::cout << "Efficient function took: " << elapsed.count() << " s\n";

    return 0;
}