Submission #800426

#	Time	Username	Problem	Language	Result	Execution time	Memory
800426		Dan4Life	Sorting (IOI15_sorting)	C++17	0 / 100	1 ms	340 KiB

sorting

#include <bits/stdc++.h>
using namespace std;
const int N = (int)2e5+10;
int n, a[N], p[N], vis[N];
 
bool chk(int m, int A[], int X[], int Y[], int P[], int Q[]){
    for(int i = 0; i < n; i++) a[i] = A[i], vis[i]=0;
    for(int i = 0; i < m; i++) swap(a[X[i]],a[Y[i]]), P[i]=Q[i]=0;
    for(int i = 0; i < n; i++) p[a[i]]=i;
    int T = 0; fill(vis,vis+n,0);
    for(int i = 0; i < n; i++){
        if(vis[i]) continue; 
        int j = i; vector<int> v; v.clear();
        while(!vis[j]){
            vis[j] = 1; v.push_back(j); j = p[j];
        }
        reverse(begin(v),end(v));
        for(int j = 0; j < (int)v.size()-1; j++){
            P[j] = v[j], Q[T] = v[j+1];
            swap(a[P[T]],a[Q[T]]);
            swap(p[a[P[T]]],p[a[Q[T]]]); T++;
        }
    }
    return T<=m;
}
 
int findSwapPairs(int N, int A[], int m, int X[], int Y[], int P[], int Q[]) {
    n = N; if(is_sorted(A,A+n)) return 0;
    for(int i = 0; i < n; i++) a[i]=A[i];
    int l = 0, r = m;
    while(l<r){
        int mid = (l+r)/2;
        if(chk(mid,A,X,Y,P,Q)) r=mid;
        else l=mid+1;
    }
    chk(l,A,X,Y,P,Q); return l;
}

Compilation message (stderr)

sorting.cpp: In function 'bool chk(int, int*, int*, int*, int*, int*)':
sorting.cpp:18:17: warning: declaration of 'j' shadows a previous local [-Wshadow]
   18 |         for(int j = 0; j < (int)v.size()-1; j++){
      |                 ^
sorting.cpp:13:13: note: shadowed declaration is here
   13 |         int j = i; vector<int> v; v.clear();
      |             ^
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:27:23: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   27 | int findSwapPairs(int N, int A[], int m, int X[], int Y[], int P[], int Q[]) {
      |                   ~~~~^
sorting.cpp:3:11: note: shadowed declaration is here
    3 | const int N = (int)2e5+10;
      |           ^

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