Submission #397091

#	Time	Username	Problem	Language	Result	Execution time	Memory
397091		Andyvanh1	Sorting (IOI15_sorting)	C++14	100 / 100	209 ms	21256 KiB

sorting

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <math.h>

using namespace std;

#define pb push_back
#define INF INT32_MAX
#define vt vector


typedef vt<int> vi;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tiii;
typedef long long ll;





#define MOD  1000000007

bool works(int n, int s[], int m, int x[],int y[], int val){
    for(int i = 0; i < val; i++){
        swap(s[x[i]],s[y[i]]);
    }
    vt<bool> visited(n);
    for(int i = 0; i < n; i++){
        visited[i] = false;
    }

    int ans = 0;
    for(int i = 0; i < n; i++){
        if(!visited[i]){
            int j = s[i];
            visited[i] = true;
            while(j!=i){
                ans++;
                visited[j] = true;
                j = s[j];

            }
        }

    }
    for(int i = val-1; i >= 0; i--){
        swap(s[x[i]],s[y[i]]);
    }

    return val>=ans;
}


int findSwapPairs(int n, int s[], int m, int x[], int y[], int p[], int q[]){
    int l = 0, r= m-1;
    while(l!=r){
        int mid = (l+r)>>1;

        if(works(n,s,m,x,y,mid)){
            r = mid;
        }else{
            l = mid+1;
        }
    }
    int op[r];
    int oq[r];
    
    for(int i = 0; i < r; i++){
        swap(s[x[i]],s[y[i]]);
    }
    int index = 0;
    vt<bool> visited(n);
    for(int i = 0; i < n; i++){
        visited[i] = false;
    }

    for(int i = 0; i < n; i++){
        if(!visited[i]){
            int j = i;
            visited[i] = true;
            vi curop;
            vi curoq;
            while(s[j]!=i){

                visited[s[j]] = true;
                curop.pb(j);
                j = s[j];
                curoq.pb(j);

            }
            for(int i = index; i < index+curop.size(); i++){
               op[i] = curop[index+curop.size()-1-i];
                oq[i] = curoq[index+curop.size()-1-i];
            }
            index+=curop.size();
        }

    }
    for(int i = index; i < r; i++){
        op[i]=1;

        oq[i]=1;
    }


    for(int i = r-1; i >= 0; i--){
        swap(s[x[i]],s[y[i]]);
    }
    int revs[n];
    for(int i = 0; i < n; i++){
        revs[s[i]] = i;
    }
    for(int i = 0; i < r; i++){
        swap(revs[s[x[i]]],revs[s[y[i]]]);
        swap(s[x[i]],s[y[i]]);
        p[i] = revs[op[i]];
        q[i] = revs[oq[i]];
    }

    return r;
}

Compilation message (stderr)

sorting.cpp: In function 'bool works(int, int*, int, int*, int*, int)':
sorting.cpp:28:32: warning: unused parameter 'm' [-Wunused-parameter]
   28 | bool works(int n, int s[], int m, int x[],int y[], int val){
      |                            ~~~~^
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:96:21: warning: declaration of 'i' shadows a previous local [-Wshadow]
   96 |             for(int i = index; i < index+curop.size(); i++){
      |                     ^
sorting.cpp:82:13: note: shadowed declaration is here
   82 |     for(int i = 0; i < n; i++){
      |             ^
sorting.cpp:96:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   96 |             for(int i = index; i < index+curop.size(); i++){
      |                                ~~^~~~~~~~~~~~~~~~~~~~
sorting.cpp:100:31: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
  100 |             index+=curop.size();
      |                               ^

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