HDU-1160 FatMouse's Speed

#include <bits/stdc++.h>
#define pb push_back
#define _for(i,a,b) for(int i = (a);i < (b);i ++)
#define INF 0x3f3f3f3f
#define sz size()

using namespace std;

const int maxn = 50003;
typedef long long ll;

struct Mouse
{
    int w;
    int s;
    int in;
    bool operator < (Mouse b)
    {
        if(w!=b.w)
        return w < b.w;
        return s > b.s;
    }
};

int main()
{
    Mouse a[1003];
    int aend = 0;
    int c,d;
    while(~scanf("%d %d",&c,&d))
    {
        a[aend].w = c;
        a[aend].in = aend+1;
        a[aend++].s = d;
    }
    sort(a,a+aend);

    int dp[aend];
    
    _for(i,0,aend)
        dp[i] = 1;
    for(int i = 1;i < aend;i ++)
        for(int j = 0;j < i;j ++)
        {
            if(a[i].w==a[j].w)
                continue;
            if(a[i].s < a[j].s)
                dp[i] = max(dp[i],dp[j]+1);
        }

    vector<int> rrnt;
    
    int ii;
    int rr = 0;

    for(int i = aend-1;i >= 0;i --)
        if(rr < dp[i])
        {
            ii = i;
            rr = dp[i];
        }
    cout << dp[ii] << endl;
    
    int rnt = dp[ii];
    rrnt.pb(a[ii].in);
    for(int i = ii-1;i >= 0;i --)
        if(dp[i]==rnt-1)
        {
            rnt --;
            rrnt.pb(a[i].in);
        }
    for(int i = rrnt.size()-1;i >= 0;i --)
        cout << rrnt[i] << endl;
    return 0;
}