Submission #705388

#	Time	Username	Problem	Language	Result	Execution time	Memory
705388		bin9638	Sorting (IOI15_sorting)	C++17	0 / 100	5 ms	4436 KiB

sorting

#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define fs first
#define sc second
#define N 1000010
#define pb push_back
#define ii pair<ll,ll>

int a[N],ktr[N],f[N],pos[N];
vector<ii>tv;

void DFS(int u)
{
    ktr[u]=1;
    if(ktr[a[u]]==0)
        DFS(a[u]);
}

int findSwapPairs(int n, int s[], int m, int x[], int y[], int p[], int q[])
{
    int res=0,l=0,r=m;
    while(l<=r)
    {
        int mid=(l+r)/2;
       // cout<<mid<<endl;
        for(int i=0;i<n;i++)
            a[i]=s[i];
        for(int i=0;i<mid;i++)
            swap(a[x[i]],a[y[i]]);
        memset(ktr,0,sizeof(ktr));
        int cnt=n;
        for(int i=0;i<n;i++)
            if(ktr[i]==0)
            {
                cnt--;
                DFS(i);
            }
        if(cnt<=mid)
        {
            r=mid-1;
            res=mid;
            for(int i=0;i<n;i++)
                f[i]=a[i];
        }else
            l=mid+1;
    }
    //for(int i=0;i<n;i++)cout<<f[i]<<" ";cout<<endl;
  res=m;
    for(int i=0;i<n;i++)
        pos[f[i]]=i;
    for(int i=0;i<n;i++)
        if(f[i]!=i)
        {
            int t=f[i];
            //cout<<i<<" "<<t<<endl;
            tv.pb({i,t});
            swap(f[i],f[pos[i]]);
            swap(pos[i],pos[t]);
        }
    //for(int i=0;i<n;i++)cout<<f[i]<<" ";cout<<endl;
    for(int i=0;i<n;i++)
    {
        a[i]=s[i];
        pos[a[i]]=i;
    }
    for(int i=0;i<res;i++)
    {
        if(i+1>tv.size())
        {
            p[i]=x[i];
            q[i]=y[i];
            continue;
        }
        swap(a[x[i]],a[y[i]]);
        swap(pos[a[x[i]]],pos[a[y[i]]]);
        int u=pos[tv[i].fs],v=pos[tv[i].sc];
        p[i]=u;
        q[i]=v;
        swap(a[u],a[v]);
        swap(pos[a[u]],pos[a[v]]);
    }
    #ifdef SKY
    for(int i=0;i<res;i++)cout<<p[i]<<" "<<q[i]<<endl;
    for(int i=0;i<n;i++)cout<<a[i]<<" ";cout<<endl;
    #endif // SKY
    return res;
}

#ifdef SKY
int main()
{
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    int n;
    cin>>n;
    int s[n];
    for(int i=0;i<n;i++)
        cin>>s[i];
    int m;
    cin>>m;
    int x[m],y[m],p[m],q[m];
    for(int i=0;i<m;i++)
    {
        cin>>x[i]>>y[i];
       // cout<<x[i]<<" "<<y[i]<<endl;
    }
    cout<<findSwapPairs(n,s,m,x,y,p,q);
    return 0;
}
#endif // SKY

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:71:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |         if(i+1>tv.size())
      |            ~~~^~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 12
• Subtask 3: 0 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26