Submission #923778

#	Time	Username	Problem	Language	Result	Execution time	Memory
923778		winter0101	Sorting (IOI15_sorting)	C++14	100 / 100	178 ms	23420 KiB

sorting

#include<bits/stdc++.h>
#include "sorting.h"
using namespace std;
#define all(fl) fl.begin(),fl.end()
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define lb lower_bound
#define ub upper_bound
#define sz(a) (int)a.size()
#define pii pair<int,int>
#define pli pair<long long,int>
#define gcd __gcd
#define lcm(x,y) x*y/__gcd(x,y)
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
for1(i,0,M-1)P[i]=Q[i]=0;
auto ck=[&](const vector<int>&p){
for1(i,0,N-1)if (p[i]!=i)return false;
return true;
};
vector<int>tmp(N);
for1(i,0,N-1)tmp[i]=S[i];
if (ck(tmp))return 0;
vector<pii>step;
auto check=[&](int mid){
vector<int>p(N);
step.clear();
for1(i,0,N-1)p[i]=S[i];
for1(i,0,mid){
swap(p[X[i]],p[Y[i]]);
}
vector<bool>vis(N);
int ans=0;
for1(i,0,N-1){
if (vis[i])continue;
auto u=i;
int cc=0;
while (true){
if (vis[u])break;
vis[u]=1;
cc++;
u=p[u];
}
ans+=cc-1;
}
for1(i,0,N-1){
while (i!=p[i]){
step.pb({p[i],p[p[i]]});
swap(p[i],p[p[i]]);
}
}
if (ans<=mid+1)return true;
return false;
};
int l=0,r=M-1,ans=M-1;
while (l<=r){
int mid=(l+r)/2;
if (check(mid)){
ans=mid;
r=mid-1;
}
else l=mid+1;
}
check(ans);
while (sz(step)<ans+1){
step.pb({0,0});
}
vector<int>pos(N),s(N);
for1(i,0,N-1)pos[S[i]]=i,s[i]=S[i];
for1(i,0,ans){
swap(pos[s[X[i]]],pos[s[Y[i]]]);
swap(s[X[i]],s[Y[i]]);
P[i]=pos[step[i].fi],Q[i]=pos[step[i].se];
swap(pos[step[i].fi],pos[step[i].se]);
swap(s[P[i]],s[Q[i]]);
}
return ans+1;
}

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