My code is :
#include<iostream>
#include<stdio.h>
#include<algorithm>
using namespace std;
struct slot{
    int start;
    int stop;
};

bool order1(const slot &lhs,const slot & rhs)
{
    return lhs.stop<rhs.stop;
}

bool order2(const slot &lhs,const slot & rhs)
{
    return lhs.start<rhs.start;
}

int main()
{
    int timemax,timemin;
    long n,i,j,temp,dp[30002],max;
    slot a[100001];
    dp[0]=0;
    scanf("%ld",&n);
    for(i=0;i<n;i++)
        scanf("%d%d",&a[i].start,&a[i].stop);

    sort(a,a+n,order2);
    timemin=a[0].start;
    stable_sort(a,a+n,order1);
    timemax=a[n-1].stop;

    for(i=0;i<=timemin;i++)
        dp[i]=0;
    for(i=timemin+1;i<=timemax;i++)
    {
        max=dp[i-1];
        while(a[j].stop<i && j<n)
        j++;
        while(a[j].stop==i)
        {
            if(a[j].start-1>=0)
                temp=1+dp[a[j].start-1];
            else
                temp=1;
            if(temp>max)
                max=temp;
            j++;
            if(j==n)
                break;
        }
        dp[i]=max;
    }



    printf("%ld\n",dp[timemax]);
}



I dont know why I am getting wrong answer on test case 1 and runtime error on Ideone.com