Submission #385051

#	Time	Username	Problem	Language	Result	Execution time	Memory
385051		qpwoeirut	Sorting (IOI15_sorting)	C++17	20 / 100	2 ms	748 KiB

sorting

#include "sorting.h"
#include <algorithm>
#include <cassert>
#include <iostream>

using namespace std;

#define val first
#define idx second

typedef pair<int,int> pii;

const int MN = 200005;

pii A[MN];

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    if (is_sorted(S, S+N)) return 0;
    int K = 0;

    if (X[0] == 0 && Y[0] == 0) {
        for (int i=0; i<N; ++i) {
            int idx = min_element(S+i, S+N) - S;
            if (idx == i) continue;
            P[K] = i;
            Q[K] = idx;
            ++K;
            swap(S[i], S[idx]);
        }
    } else if (X[0] == 0 && Y[0] == 1) {
        for (int i=2; i<N; ++i) {
            int idx = min_element(S+i, S+N) - S;
            if (idx == i) continue;
            swap(S[0], S[1]);

            P[K] = i;
            Q[K] = idx;
            ++K;
            swap(S[i], S[idx]);
        }
        //for (int i=0; i<N; ++i) { cerr << S[i] << ' '; } cerr << endl;
        while (N > 2 && S[0] + S[1] > 1) {
            swap(S[0], S[1]);

            if (S[0] < S[1]) {
                P[K] = 1;
                swap(S[1], S[2]);
            } else {
                P[K] = 0;
                swap(S[0], S[2]);
            }
            Q[K] = 2;
            ++K;

            for (int i=2; i+1<N; ++i) {
                if (S[i] > S[i+1]) {
                    swap(S[0], S[1]);

                    swap(S[i], S[i+1]);
                    P[K] = i;
                    Q[K] = i+1;
                    ++K;
                } else break;
            }
        }

        swap(S[0], S[1]);
        if (S[0] == 1) {
            assert(S[1] == 0);
            P[K] = 0;
            Q[K] = 0;
            ++K;
            swap(S[0], S[1]);
        }
    } else assert(0);

    //for (int i=0; i<N; ++i) { cerr << S[i] << ' '; } cerr << endl;
    assert(is_sorted(S, S+N));

    assert(K <= M);
    return K;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:23:45: warning: conversion from 'long int' to 'int' may change value [-Wconversion]
   23 |             int idx = min_element(S+i, S+N) - S;
      |                       ~~~~~~~~~~~~~~~~~~~~~~^~~
sorting.cpp:32:45: warning: conversion from 'long int' to 'int' may change value [-Wconversion]
   32 |             int idx = min_element(S+i, S+N) - S;
      |                       ~~~~~~~~~~~~~~~~~~~~~~^~~

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