Submission #314817

#	Time	Username	Problem	Language	Result	Execution time	Memory
314817		amunduzbaev	Sorting (IOI15_sorting)	C++14	0 / 100	1 ms	512 KiB

sorting

///#include "grader.cpp"
#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
#define pb(a) push_back(a)
const int N=800005;
int n,s[N],x[N],y[N],tmp[N],pos[N];
vector<pair<int,int>> ans;
bool check(int m){
    int i;
    for(i=0;i<n;i++) tmp[i]=s[i];
    for(i=0;i<n;i++) swap(tmp[x[i]],tmp[y[i]]);
    for(i=0;i<n;i++) pos[tmp[i]]=i;
    vector<pair<int,int>>swaps;
    for(i=0;i<n;i++){
        if(pos[i]==i) continue;
        swaps.push_back({tmp[i],pos[tmp[i]]});
        swap(tmp[i],tmp[pos[i]]);
        swap(pos[tmp[i]], pos[tmp[pos[i]]]);
    }
    if(swaps.size() > m) return 0;
    ans.clear();
    for(i=0;i<n;i++) tmp[i]=s[i],pos[tmp[i]]=i;

    for(i=0;i<swaps.size();i++){
        int a=pos[swaps[i].first], b=pos[swaps[i].second];
        ans.push_back({a,b});
        swap(tmp[x[i]],tmp[y[i]]);
        swap(pos[tmp[x[i]]], pos[tmp[y[i]]]);
        swap(tmp[a],tmp[b]);
        swap(pos[tmp[a]], pos[tmp[b]]);
    }
    for(; i<m;i++)
        ans.push_back({0, 0});
    return 1;
}

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++) s[i]=S[i];
    for(int i=0;i<M;i++) x[i]=X[i], y[i]= Y[i];

    int l=0,r=M;
    while(l<r) {
        int mid=(l+r)/2;
        if(check(mid) <= M) r=mid;
        else l=mid+1;
    }
    check(l);
    for(int i=0;i<l;i++){
        p[i]=ans[i].first, q[i]=ans[i].second;
    }
    return l;
}

Compilation message (stderr)

sorting.cpp: In function 'bool check(int)':
sorting.cpp:21:21: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   21 |     if(swaps.size() > m) return 0;
      |        ~~~~~~~~~~~~~^~~
sorting.cpp:25:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for(i=0;i<swaps.size();i++){
      |             ~^~~~~~~~~~~~~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:38:76: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   38 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int p[], int q[]) {
      |                                                                            ^
sorting.cpp:6:11: note: shadowed declaration is here
    6 | const int N=800005;
      |           ^

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