vector 容量capacity size 不同

#include<iostream>
#include<cstring>
#include<algorithm>
#include<ctime>

using namespace std;

int main()
{
    clock_t t = clock();

    int l = 1;
    while(1)
    {
        l ++;
        if(l > 4e8) break; // 4亿
    }
    cout << (double)(clock() - t) / 1000 / 1000 << endl;

    vector<int> a;
    l = 1;
    t = clock();
    while(1)
    {
        a.push_back(l);
        l ++;
        if(l > 1e5) break;
    }
    cout << (double)(clock() - t) / 1000 / 1000 << endl;

    printf("a.capacity = %d\n", a.capacity());
    printf("a.data = %lld\n", a.data());
    printf("a.front = %d\n", a.front());
    printf("a.back = %d\n", a.back());
    printf("a.begin = %lld\n", a.begin());
    printf("a.end = %lld\n", a.end());

    t = clock();
    printf("a.size = %d\n", a.size());
    cout << (double)(clock() - t) / 1000 / 1000 << endl;

    return 0;
}

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选中目标 shift ctrl L 选中所有相同目标

使用 sstream

#include<iostream>
#include<algorithm>
#include<cstring>
#include<sstream>

using namespace std;

int main()
{
    stringstream sin;

    string line;

    getline(cin, line);

    sin << line;

    string str;

    while(sin >> str) cout << str << endl;

    return 0;
}

判断闰年

bool isLeapYear(int year) {
    if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) return true;
    return false;
}