Submission #1134562

#	Time	Username	Problem	Language	Result	Execution time	Memory
1134562		ackhava	Sorting (IOI15_sorting)	C++20	74 / 100	1096 ms	47268 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
#define REP(v, i, j) for (int v = i; v != j; v++)
#define FORI(v) for (auto i : v)
#define FORJ(v) for (auto j : v)

#define OUT(v, a) \
    FORI(v)       \
    cout << i << a;
#define OUTS(v, a, b)      \
    cout << v.size() << a; \
    OUT(v, b)
#define in(a, n) \
    REP(i, 0, n) \
    cin >> a[i];

#define SORT(v) sort(begin(v), end(v))
#define REV(v) reverse(begin(v), end(v))
#define MEMSET(m) memset(m, -1, sizeof m)

#define pb push_back
#define fi first
#define se second

#define detachIO                      \
    ios_base::sync_with_stdio(false); \
    cin.tie(0);                       \
    cout.tie(0);
    
using namespace std;


typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<pii, pii> piiii;

const int MOD = 1e9+7;

struct modint {
    long long val;

    modint() = default;
    modint(int _val): val(_val){}
    modint operator+(modint b){ return ((this->val + b.val)%MOD); }
    modint operator-(modint b){ return ((MOD + this->val - b.val)%MOD); }
    modint operator*(modint b){ return ((this->val * b.val)%MOD); }
    modint operator^(int a){
        if(a==0)return 1;
        if(a==1)return *this;
        return (((*this)*(*this))^(a>>1))*((*this)^(a&1)); 
    }
};

modint invert(modint a){
    return a^(MOD-2);
}

modint operator/(modint a, modint b){
    return a*invert(b);
}

unordered_map<int,int> amp;
unordered_map<int,int> vmp;

int _findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
	unordered_set<int> off;
	vector<int> vec,v2;
	REP(i,0,N){
		vec.pb(i);
	}
	v2=vec;
	REP(i,0,M){
		swap(vec[X[M-i-1]],vec[Y[M-i-1]]);
	}
	REP(i,0,M){
		swap(vec[X[i]],vec[Y[i]]);
	}
	assert(v2==vec);
	REP(i,0,M){
		swap(vec[X[M-i-1]],vec[Y[M-i-1]]);
	}
	vector<int> arr,a2;
	REP(i,0,N)arr.pb(S[i]);
	a2=arr;
	REP(i,0,M){
		P[i]=Q[i]=0;
	}
	REP(i,0,N){
		amp[arr[i]]=i;
		vmp[vec[i]]=i;
	}
	unordered_map<int,int> va;
	vector<int> corr;
	REP(i,0,N){
		va[vec[i]]=arr[i];
	}
	int rounds=0;
	REP(i,0,N){
		if(va[i]==i)continue;
		vector<int> loop;
		int x=i;
		do{
			loop.pb(x);
			x=va[x];
		}while(x!=i);
		rounds+=loop.size()-1;
		FORJ(loop)va[j]=j;
	}

	int _M=M;
	arr=a2;
	vec=v2;
	REP(i,0,M){
		swap(vec[X[M-i-1]],vec[Y[M-i-1]]);
	}
	REP(i,0,N){
		amp[arr[i]]=i;
		vmp[vec[i]]=i;
	}
	REP(i,0,N){
		if(arr[i]!=vec[i])off.insert(arr[i]);
	}

	REP(i,0,M){
		if(!off.size())break;
		int v=Y[i];
		int a=X[i];
		amp[arr[a]]=-1;
		amp[arr[v]]=-1;
		vmp[vec[a]]=-1;
		vmp[vec[v]]=-1;

		swap(arr[a],arr[v]);
		swap(vec[a],vec[v]);
		
		amp[arr[a]]=a;
		amp[arr[v]]=v;
		vmp[vec[a]]=a;
		vmp[vec[v]]=v;

		if(arr[a]==vec[a])off.erase(arr[a]);
		if(arr[v]==vec[v])off.erase(arr[v]);

		if(!off.size())break;
		auto x=*off.begin();
		a=amp[x];
		v=vmp[x];
		amp[arr[a]]=-1;
		amp[arr[v]]=-1;
		vmp[vec[a]]=-1;
		vmp[vec[v]]=-1;

		swap(arr[a],arr[v]);
		
		amp[arr[a]]=a;
		amp[arr[v]]=v;
		vmp[vec[a]]=a;
		vmp[vec[v]]=v;

		if(arr[a]==vec[a])off.erase(arr[a]);
		if(arr[v]==vec[v])off.erase(arr[v]);
		
		P[i]=a;
		Q[i]=v;
	}
	if(arr!=vec)return -1;
	if(off.size())return 1;

	SORT(arr);
	if(a2==arr)return 0;

	REP(i,0,_M){
		swap(a2[X[i]],a2[Y[i]]);
		swap(a2[P[i]],a2[Q[i]]);
		if(a2==arr)return i+1;
	}
	if(a2==arr)return M;
	return -1;
}


int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
	int l=0,r=M;
	int ans=M;
	assert(_findSwapPairs(N,S,M,X,Y,P,Q)!=-1);
	while(l<=r){
		int m=(l+r)/2;
		if(_findSwapPairs(N,S,m,X,Y,P,Q)==-1)l=m+1;
		else r=m-1,ans=m;
	}
	return _findSwapPairs(N,S,ans,X,Y,P,Q);
}

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