Submission #389616

#	Time	Username	Problem	Language	Result	Execution time	Memory
389616		faresbasbs	Sorting (IOI15_sorting)	C++14	0 / 100	2 ms	716 KiB

sorting

#include <bits/stdc++.h>
#include "sorting.h"
using namespace std;
vector<int> v,v2,st,e,l,r,ls,rs;
bool seen[200001];
int n,rt;

void dfs(int curr){
    if(curr != rt){
        l.push_back(rt);
        r.push_back(curr);
    }
    seen[curr] = 1;
    if(!seen[v2[curr]]){
        dfs(v2[curr]);
    }
}

bool work(int mid){
    memset(seen,0,sizeof seen);
    l.clear(),r.clear(),ls.clear(),rs.clear();
    v2 = v;
    for(int i = 0 ; i < mid ; i += 1){
        swap(v2[st[i]],v2[e[i]]);
    }
    int num = n;
    for(int i = 0 ; i < n ; i += 1){
        if(seen[i]){
            continue;
        }
        num -= 1;
        rt = i;
        dfs(i);
    }
    if(num > mid){
        return false;
    }
    vector<int> ind(n);
    v2 = v;
    for(int i = 0 ; i < n ; i += 1){
        ind[v2[i]] = i;
    }
    for(int i = 0 ; i < mid ; i += 1){
        int x = st[i] , y = e[i];
        swap(ind[v2[x]],ind[v2[y]]);
        swap(v2[x],v2[y]);
        x = l[i] , y = r[i];
        ls.push_back(ind[x]);
        rs.push_back(ind[y]);
        swap(v2[ind[x]],v2[ind[y]]);
        swap(ind[x],ind[y]);
    }
    return true;
}

int findSwapPairs(int N , int s[] , int m , int x[] , int y[] , int p[] , int q[]){
    n = N;
    for(int i = 0 ; i < n ; i += 1){
        v.push_back(s[i]);
    }
    for(int i = 0 ; i < m ; i += 1){
        st.push_back(x[i]) , e.push_back(y[i]);
    }
    int first = -1 , last = m;
    while(last-first > 1){
        int mid = (first+last)/2;
        if(work(mid)){
            last = mid;
        }else{
            first = mid;
        }
    }
    for(int i = 0 ; i < (int)ls.size() ; i += 1){
        p[i] = ls[i] , q[i] = rs[i];
    }
    return last;
}

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