Submission #834017

#	Time	Username	Problem	Language	Result	Execution time	Memory
834017		Victor	Sorting (IOI15_sorting)	C++17	36 / 100	28 ms	852 KiB

sorting

#include "sorting.h"

#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define per(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back

typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;

const ll INF = 1'000'000'007;

bool isSorted(int N, int S[]) {
    rep(i,0,N) if(S[i]!=i) return false;
    return true;
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    P[0] = 0;
    Q[0] = 0;

    rep(i,0,M+1) {
        //cout<<"i = "<<i<<endl;
        //rep(i,0,N) cout<<S[i]<<' ';
        //cout<<endl<<endl;
        
        if(isSorted(N,S)) return i;
        swap(S[X[i]],S[Y[i]]);
        P[i]=Q[i]=0;
        vi swaps;
        per(j,0,N) if(S[j]!=j) swaps.pb(j);

        if(!sz(swaps)) continue;

        int id=rand()%sz(swaps);
        int j=swaps[id],pos;
        rep(k,0,N) if(S[k]==j) {
            pos=k;
            break;
        }
        P[i]=j;
        Q[i]=pos;
        swap(S[j],S[pos]);
    }
    return 1;
}
/*
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "sorting.h"

static char _buffer[1024];
static int _currentChar = 0;
static int _charsNumber = 0;
static FILE *_inputFile, *_outputFile;

static inline int _read() {
    if (_charsNumber < 0) {
        exit(1);
    }
    if (!_charsNumber || _currentChar == _charsNumber) {
        _charsNumber = (int)fread(_buffer, sizeof(_buffer[0]), sizeof(_buffer), _inputFile);
        _currentChar = 0;
    }
    if (_charsNumber <= 0) {
        return -1;
    }
    return _buffer[_currentChar++];
}

static inline int _readInt() {
    int c, x, s;
    c = _read();
    while (c <= 32) c = _read();
    x = 0;
    s = 1;
    if (c == '-') {
        s = -1;
        c = _read();
    }
    while (c > 32) {
        x *= 10;
        x += c - '0';
        c = _read();
    }
    if (s < 0) x = -x;
    return x;
}


int main()
{
	_inputFile = fopen("sorting.in", "rb");
	int N, M;
	N = _readInt();
	int *S = (int*)malloc(sizeof(int) * (unsigned int)N);
	for (int i = 0; i < N; ++i)
		S[i] = _readInt();
	M = _readInt();
	int *X = (int*)malloc(sizeof(int) * (unsigned int)M), *Y = (int*)malloc(sizeof(int) * (unsigned int)M);
	for (int i = 0; i < M; ++i) {
	    X[i] = _readInt();
	    Y[i] = _readInt();
	}
	int *P = (int*)malloc(sizeof(int) * (unsigned int)M), *Q = (int*)malloc(sizeof(int) * (unsigned int)M);
	int ans = findSwapPairs(N, S, M, X, Y, P, Q);
	printf("%d\n", ans);
	for (int i = 0; i < ans; ++i)
		printf("%d %d\n", P[i], Q[i]);
	return 0;
}
*/

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:46:22: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   46 |         int id=rand()%sz(swaps);
      |                      ^
sorting.cpp:54:21: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   54 |         swap(S[j],S[pos]);
      |                     ^~~

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