洛谷编译失败QAQ 求助大佬

#include <iostream>
#include <algorithm>
#include <math.h>

using namespace std;

typedef struct t_data
{
    string s;
    int y, m, d, ind;

} data;

data datas[105];

bool cmp(data &a, data &b)
{
    if (a.y != b.y)
        return a.y < b.y;
    else
    {
        if (a.m != b.m)
            return a.m < b.m;
        else if (a.m == b.m && a.d != b.d)
            return a.d < b.d;
        else if (a.m == b.m && a.d == b.d)
            return a.ind > b.ind;
    }
}

int main()
{
    int n;
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        cin >> datas[i].s >> datas[i].y >> datas[i].m >> datas[i].d;
        datas[i].ind = i;
    }

    sort(datas, datas + n, cmp);

    for (int i = 0; i < n; i++)
    {
        cout << datas[i].s << endl;
    }

    return 0;
}