/*
* @Author: eleven
* @Date:   2017-05-21 02:50:38
* @Last Modified by:   eleven
* @Last Modified time: 2018-02-09 14:49:14
*/

// Status : AC ( works with stable_sort )
// doesn't works with sort

#include <bits/stdc++.h>

using namespace std;

#define SIZE 150005

struct team{
    int id;
    int solved;
}teams[SIZE];

bool foo(team lhs, team rhs){
return lhs.solved > rhs.solved;
}

void print(int n ){

    for(int i= 0; i<n ; ++i){
        cout<<teams[i].id<<" "<<teams[i].solved<<'\n';
    }
}


int main(){


    //freopen("in","r",stdin);
    //freopen("out","w",stdout);

    int n ;

    cin>>n;

    for(int i = 0; i<n ; ++i){
        cin>>teams[i].id>>teams[i].solved;
    }

    stable_sort(teams,teams+n ,foo);

    print(n);

    return 0;

}

I don't know why, but i have tha same problem. WA with sort, AC with stable_sort *go to read faq's*

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>
using namespace std;

pair <int, int> a[150000];
int n;

bool comp(pair <int, int> a, pair <int, int> b)
{
    return a.first > b.first;
}
int main()
{
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        scanf("%d%d", &a[i].second, &a[i].first);
    stable_sort(a, a + n, comp);
    //sort(a, a+n,comp);
    for (int i=0;i<n;i++)
        printf("%d %d\n", a[i].second, a[i].first);
    return 0;
}

OK, i've found yhe answere - stable_sort keeps the relative order berween equal elements... because this is stable sort))