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Subsequence.java
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Subsequence.java
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package coding.POJ.ID_3061;
/*
* Subsequence.java
*
* Version:
* $1.0$
*
* Revisions:
* $1.0$
*/
import coding.POJ.POJMain;
import com.fengkeyleaf.io.ProcessingFile;
import com.fengkeyleaf.io.ReadFromStdOrFile;
import com.fengkeyleaf.util.MyCollections;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
/**
* Subsequence
* @see <a href=http://poj.org/problem?id=3061>Subsequence</a>
*
* @author Xiaoyu Tongyang, or call me sora for short
* @see <a href="https://fengkeyleaf.com">person website</a>
*/
public final class Subsequence implements ProcessingFile {
private List<Integer> numbers;
private int target;
public Subsequence( int[] nums, int target ) {
this.target = target;
numbers = new ArrayList<>( nums.length );
for ( int num : nums ) {
numbers.add( num );
}
// System.out.println( doTheAlgorithm() );
System.out.println( doTheAlgorithmLinear() );
}
public Subsequence( String fileName ) {
ReadFromStdOrFile.readFromFile( fileName, this );
}
@Override
public void processingFile( Scanner sc ) {
int numberOfTestCases = Integer.parseInt( sc.nextLine().strip() );
for ( int i = 0; i < numberOfTestCases; i++ ) {
int counter = 0;
while ( counter < 2 ) {
String content = sc.nextLine().strip();
if ( ReadFromStdOrFile.skipInputData(
content, false ) )
continue;
String[] nums = content.split( ReadFromStdOrFile.PATTERN_WHITE_CHARACTER );
if ( counter == 0 ) {
numbers = new ArrayList<>( Integer.parseInt( nums[ 0 ] ) );
target = Integer.parseInt( nums[ 1 ] );
}
else if ( counter == 1 ) {
for ( String num : nums )
numbers.add( Integer.parseInt( num ) );
}
counter++;
}
// System.out.println( doTheAlgorithm() );
System.out.println( doTheAlgorithmLinear() );
}
}
private int doTheAlgorithm() {
if ( numbers == null || numbers.isEmpty() ) return 0;
// no such a sequence exist
// given non-positive S
if ( target <= 0 ) return 1;
// get cumulative sum
for ( int i = 1; i < numbers.size(); i++ )
numbers.set( i, numbers.get( i - 1 ) + numbers.get( i ) );
int maxSum = numbers.get( numbers.size() - 1 );
if ( target > maxSum )
return 0;
int minLength = numbers.size();
// give non-positive S, no need to check if i is out of index
for ( int i = 0; numbers.get( i ) + target <= maxSum; i++ ) {
// S_t - S_i >= S -> S_t >= S + S_i
int endIndex = MyCollections.ceilBound( numbers, i, i + minLength,
numbers.get( i ) + target );
minLength = Math.min( minLength, endIndex - i );
}
return minLength;
}
private int doTheAlgorithmLinear() {
if ( numbers == null || numbers.isEmpty() ) return 0;
// no such a sequence exist
// given non-positive S
if ( target <= 0 ) return 1;
int len = numbers.size();
int minLength = len + 1;
int start = 0;
int end = 0;
int sum = 0;
while ( true ) {
// find the sequence
// greater than or equal to S
while ( end < len &&
sum < target )
sum += numbers.get( end++ );
// no sequence greater than S at this point
// stop searching, break
if ( sum < target ) break;
// reset searching status
minLength = Math.min( minLength, end - start );
sum -= numbers.get( start++ );
}
return minLength > len ? 0 : minLength;
}
private static
void testOne() {
// int[] nums = { 1, 2, 3, 4, 5 };
int target = 11;
// new Subsequence( nums, target ); // 3
//
// int[] nums2 = { 5, 1, 3, 5, 10, 7, 4, 9, 2, 8 };
// target = 15;
// new Subsequence( nums2, target ); // 2
// int[] nums3 = { 1, 2, 3, 4, 5 };
// target = 0;
// new Subsequence( nums3, target ); // 1
//
// int[] nums4 = { 1, 2, 3, 4, 5 };
// target = 1;
// new Subsequence( nums4, target ); // 1
int[] nums5 = { 1, 2 };
target = 0;
new Subsequence( nums5, target ); // 1
int[] nums6 = {};
new Subsequence( nums6, target ); // 0
}
public static
void main( String[] args ) {
testOne();
new Subsequence( POJMain.getFilePathPOJ( 3061, 1 ) );
}
}