Submission #314821

#	Time	Username	Problem	Language	Result	Execution time	Memory
314821		amunduzbaev	Sorting (IOI15_sorting)	C++14	100 / 100	378 ms	23348 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<m;i++)swap(tmp[x[i]],tmp[y[i]]);
    for(i=0;i<n;i++)pos[tmp[i]]=i;
    vector<pair<int,int>    >sw;
    ans.clear();
    for(i=0;i<n;i++){
        if(pos[i]==i)continue;
        sw.push_back({tmp[i],tmp[pos[i]]});
        swap(tmp[pos[i]],tmp[i]);
        swap(pos[tmp[pos[i]]],pos[tmp[i]]);
    }
    if(sw.size()>m)return 0;
    for(i=0;i<n;i++)tmp[i]=s[i],pos[tmp[i]]=i;
    for(i=0;i<sw.size();i++){
        swap(tmp[x[i]],tmp[y[i]]);
        swap(pos[tmp[x[i]]],pos[tmp[y[i]]]);
        ans.push_back({pos[sw[i].first],pos[sw[i].second]});
        swap(tmp[pos[sw[i].first]],tmp[pos[sw[i].second]]);
        swap(pos[tmp[pos[sw[i].first]]],pos[tmp[pos[sw[i].second]]]);
    }
    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)) 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:22:17: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |     if(sw.size()>m)return 0;
      |        ~~~~~~~~~^~
sorting.cpp:24:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |     for(i=0;i<sw.size();i++){
      |             ~^~~~~~~~~~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:35:76: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   35 | 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: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26