Submission #1040181

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040181		Zicrus	Sorting (IOI15_sorting)	C++17	74 / 100	1047 ms	18776 KiB

sorting

#pragma GCC optimize("O3","unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")

#include <bits/stdc++.h>
#include "sorting.h"
using namespace std;
 
typedef int ll;
 
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P1[], int Q1[]) {
    vector<ll> h(N);
    for (int i = 0; i < N; i++) h[i] = S[i];
 
    ll ooo = 0;
    for (int i = 0; i < N; i++) {
        if (h[i] != i) ooo++;
    }
    if (ooo == 0) return 0;
    
vector<int> P(N), Q(N); //
 
    vector<ll> revH(N);
    for (int i = 0; i < N; i++) {
        revH[h[i]] = i;
    }
 
    ll res1 =0;
    ll low = 1, high = N;
    while (low < high) {
        ll g = max((low + high) / 2, high - 20000);
 
        ll res = 0;
        vector<ll> s = h;
        vector<ll> order = s;
        vector<ll> revOrd = revH, revS = revH;
        for (int j = 0; j < g; j++) {
            swap(order[X[j]], order[Y[j]]);
            swap(revOrd[order[X[j]]], revOrd[order[Y[j]]]);
        }
        int id1 = -1;
        for (int i = 0; i < g; i++) {
            swap(s[X[i]], s[Y[i]]);
            swap(revS[s[X[i]]], revS[s[Y[i]]]);
            int firstOut = -1, id = -1;
            for (int j = id1+1; j < N; j++) {
                if (order[j] != j) {
                    firstOut = order[id = j];
                    break;
                }
            }
            id1 = id;
            if (firstOut == -1) {
                P[res] = Q[res] = 0;
                res++;
            }
            else {
                ll iter = revOrd[id];
                ll v = order[iter];
 
                ll id1 = revS[firstOut];
                ll id2 = revS[v];
                swap(s[id1], s[id2]);
                swap(revS[s[id1]], revS[s[id2]]);
                swap(order[iter], order[id]);
                swap(revOrd[order[iter]], revOrd[order[id]]);
                P[res] = id1;
                Q[res] = id2;
                res++;
            }
        }
        ll ooo = 0;
        for (int i = g; i < N; i++) {
            if (s[i] != i) ooo++;
        }
        if (ooo == 0) {
            res1 = res;
            high = res;
 
            for (int i = 0; i < res; i++) {
                P1[i] = P[i];
                Q1[i] = Q[i];
            }
        }else {
            low = g+1;
        }
    }
	return res1;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:60:20: warning: declaration of 'id1' shadows a previous local [-Wshadow]
   60 |                 ll id1 = revS[firstOut];
      |                    ^~~
sorting.cpp:40:13: note: shadowed declaration is here
   40 |         int id1 = -1;
      |             ^~~
sorting.cpp:71:12: warning: declaration of 'ooo' shadows a previous local [-Wshadow]
   71 |         ll ooo = 0;
      |            ^~~
sorting.cpp:14:8: note: shadowed declaration is here
   14 |     ll ooo = 0;
      |        ^~~
sorting.cpp:10:39: warning: unused parameter 'M' [-Wunused-parameter]
   10 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P1[], int Q1[]) {
      |                                   ~~~~^

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