Tasks Details
easy
Minimize the value |(A[0] + ... + A[P-1]) - (A[P] + ... + A[N-1])|.
Task Score
100%
Correctness
100%
Performance
100%
A non-empty array A consisting of N integers is given. Array A represents numbers on a tape.
Any integer P, such that 0 < P < N, splits this tape into two non-empty parts: A[0], A[1], ..., A[P − 1] and A[P], A[P + 1], ..., A[N − 1].
The difference between the two parts is the value of: |(A[0] + A[1] + ... + A[P − 1]) − (A[P] + A[P + 1] + ... + A[N − 1])|
In other words, it is the absolute difference between the sum of the first part and the sum of the second part.
For example, consider array A such that:
A[0] = 3 A[1] = 1 A[2] = 2 A[3] = 4 A[4] = 3We can split this tape in four places:
- P = 1, difference = |3 − 10| = 7
- P = 2, difference = |4 − 9| = 5
- P = 3, difference = |6 − 7| = 1
- P = 4, difference = |10 − 3| = 7
Write a function:
class Solution { public int solution(int[] A); }
that, given a non-empty array A of N integers, returns the minimal difference that can be achieved.
For example, given:
A[0] = 3 A[1] = 1 A[2] = 2 A[3] = 4 A[4] = 3the function should return 1, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [2..100,000];
- each element of array A is an integer within the range [−1,000..1,000].
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 8 minutes
Notes
not defined yet
Task timeline
Code: 11:47:02 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Math
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int N = A.length;
int [] after = new int[N];
after[N-1] = A[N-1];
for(int i=N-2;i>=0;i--) {
after[i] = after[i+1] + A[i];
}
int min = Math.abs(after[0] - after[1]*2);
for(int P=2;P<N;P++) {
int temp = Math.abs(after[0] - after[P]*2);
if(min > temp)
min = temp;
}
return min
}
}
Analysis
Compile error
Solution.java:6: error: ';' expected
import java.util.Math
^
Solution.java:23: error: ';' expected
return min
^
2 errors
Code: 11:48:06 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Math;
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int N = A.length;
int [] after = new int[N];
after[N-1] = A[N-1];
for(int i=N-2;i>=0;i--) {
after[i] = after[i+1] + A[i];
}
int min = Math.abs(after[0] - after[1]*2);
for(int P=2;P<N;P++) {
int temp = Math.abs(after[0] - after[P]*2);
if(min > temp)
min = temp;
}
return min;
}
}
Analysis
Compile error
Solution.java:6: error: cannot find symbol
import java.util.Math;
^
symbol: class Math
location: package java.util
1 error
Code: 11:48:50 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.lang.Math;
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int N = A.length;
int [] after = new int[N];
after[N-1] = A[N-1];
for(int i=N-2;i>=0;i--) {
after[i] = after[i+1] + A[i];
}
int min = Math.abs(after[0] - after[1]*2);
for(int P=2;P<N;P++) {
int temp = Math.abs(after[0] - after[P]*2);
if(min > temp)
min = temp;
}
return min;
}
}
Analysis
Code: 11:49:07 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.lang.Math;
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int N = A.length;
int [] after = new int[N];
after[N-1] = A[N-1];
for(int i=N-2;i>=0;i--) {
after[i] = after[i+1] + A[i];
}
int min = Math.abs(after[0] - after[1]*2);
for(int P=2;P<N;P++) {
int temp = Math.abs(after[0] - after[P]*2);
if(min > temp)
min = temp;
}
return min;
}
}
Analysis
Code: 11:49:20 UTC,
java,
final,
score:
100
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.lang.Math;
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int N = A.length;
int [] after = new int[N];
after[N-1] = A[N-1];
for(int i=N-2;i>=0;i--) {
after[i] = after[i+1] + A[i];
}
int min = Math.abs(after[0] - after[1]*2);
for(int P=2;P<N;P++) {
int temp = Math.abs(after[0] - after[P]*2);
if(min > temp)
min = temp;
}
return min;
}
}Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N)
expand all
Correctness tests
1.
0.031 s
OK
2.
0.030 s
OK
1.
0.087 s
OK
1.
0.064 s
OK
1.
0.036 s
OK
1.
0.034 s
OK
1.
0.074 s
OK
expand all
Performance tests
1.
0.156 s
OK
1.
0.174 s
OK
1.
0.494 s
OK
2.
0.388 s
OK
1.
0.687 s
OK
2.
0.486 s
OK
1.
0.441 s
OK
1.
0.453 s
OK
2.
0.565 s
OK
3.
0.430 s
OK