9/22/25, 12:48 PM
DIY1.cpp
演算法作業\DIY1.cpp
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#include<iostream>
#include<random>
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#include<vector>
#include<fstream>
#include<cmath>
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//使用較為不準的ctime不影響實驗結果，因主要的不準量會是random pivot造成的
#include<ctime>
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using namespace std;
const int SIZE = 1000000;
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vector<int> input(SIZE*3);
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void Read() {
fstream input1("1000000.case1.in");
fstream input2("1000000.case2.in");
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fstream input3("1000000.case3.in");
int i = 0, iMax = 0, temp;
string line;
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getline(input1, line);
getline(input1, line);
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for( iMax = SIZE; i < iMax; i++ ) {
input1 >> temp >> input[i];
}
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getline(input2, line);
getline(input2, line);
for( iMax = SIZE * 2; i < iMax; i++ ) {
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input2 >> temp >> input[i];
}
getline(input3, line);
getline(input3, line);
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for( iMax = SIZE * 3; i < iMax; i++ ) {
input3 >> temp >> input[i];
}
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input1.close();
input2.close();
input3.close();
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}
int f( int n ) { // how many random numbers to pick
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//return 1;
if( n < 1000 ) return 1;
if( n < 10000 ) return 3;
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}
return 5;
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int tphp[5];
int temp, len;
void swap( int a, int b ) {
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DIY1.cpp
temp = tphp[a];
tphp[a] = tphp[b];
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tphp[b] = temp;
}
int thre = 50; //小於這個值就取一個，大於取三個
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int GetR( int low, int high ) {
len = high - low + 1;
//return rand() % len + low;
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if( len < thre ) return rand() % ( len ) + low;
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if( input[tphp[0]] < input[tphp[1]] ) {
if( input[tphp[1]] < input[tphp[2]] ) return tphp[1];
if( input[tphp[0]] < input[tphp[2]] ) return tphp[2];
for( int i = 0; i < 3; i++ ) tphp[i] = rand() % ( len ) + low;
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return tphp[0];
}
if( input[tphp[0]] < input[tphp[2]] ) return tphp[0];
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if( input[tphp[1]] < input[tphp[2]] ) return tphp[2];
return tphp[1];
}
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void InsertionSort(vector<int>& data, int low, int high ) {
for( int i = low; i <= high; i++ ) {
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int j = i - 1, key = data[i];
while( j >= 0 && data[j] > key ) {
data[j+1] = data[j];
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j--;
}
data[j+1] = key;
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}
}
int RandomizedPartition(vector<int>& data, int low, int high){
int r = GetR( low, high );
int i = low, pivot, temp;
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temp = data[r];
data[r] = data[high];
data[high] = temp;
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pivot = data[high];
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for( int j = low; j < high; j++ ) {
if( data[j] <= pivot ) {
temp = data[j];
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data[j] = data[i];
data[i] = temp;
i++;
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}
}
temp = data[i];
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data[i] = data[high];
data[high] = temp;
return i;
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DIY1.cpp
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}
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int thre1 = 30; //小於這個大小用insertion
void QuickSortSubVector(vector<int>& data, int low, int high) {
if( high - low < thre1 ) InsertionSort( data, low, high );
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else if( low < high ) {
int mid = RandomizedPartition( data, low, high );
QuickSortSubVector( data, mid+1, high );
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QuickSortSubVector( data, low, mid-1 );
}
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bool check( int num ) {
int k = 0;
}
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for( int i = 0; i < num; i++ ) {
//cout<< input[i]<< endl;
if( k > input[i] ) return 0;
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k = input[i];
}
return 1;
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}
int main() {
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Read();
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QuickSortSubVector(input, SIZE*2, SIZE*3);
clock_t end = clock();
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double cpu_time_used = ((double)(end - start)) / CLOCKS_PER_SEC;
cout<< "time: "<< cpu_time_used<< endl;
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//cout<< check(SIZE*3);
return 0;
clock_t start = clock();
}
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