Submission #800400

#	Time	Username	Problem	Language	Result	Execution time	Memory
800400		Dan4Life	Sorting (IOI15_sorting)	C++17	20 / 100	1 ms	340 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
const int mxN = (int)2e5+10;
int n, tot, a[mxN], t[mxN], x[mxN], y[mxN], p[mxN], vis[mxN];
 
int chk(int m, int P[], int Q[]){
    for(int i = 0; i < n; i++) a[i] = t[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;
    tot = 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; if(vis[p[j]]) break; 
            P[tot]=j,Q[tot++]=p[j], j = p[j];
        }
    }
    return (tot<=m)?m:mxN;
}
 
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] = t[i] = A[i];
        x[i] = X[i], y[i] = Y[i];
    }
    int l = 0, r = n;
    while(l<r){
        int mid = (l+r)/2;
        if(chk(mid,P,Q)<=mid) r=mid;
        else l=mid+1;
    }
    return chk(l,P,Q);
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:23:39: warning: unused parameter 'm' [-Wunused-parameter]
   23 | int findSwapPairs(int N, int A[], int m, int X[], int Y[], int P[], int Q[]) {
      |                                   ~~~~^

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