Test results - Codility

Tasks Details

easy

1. CountTriangles

Count the number of triangles that can be built from a given set of edges.

Task Score

100%

Correctness

100%

Performance

100%

An array A consisting of N integers is given. A triplet (P, Q, R) is triangular if it is possible to build a triangle with sides of lengths A[P], A[Q] and A[R]. In other words, triplet (P, Q, R) is triangular if 0 ≤ P < Q < R < N and:

A[P] + A[Q] > A[R],

A[Q] + A[R] > A[P],

A[R] + A[P] > A[Q].

For example, consider array A such that:

A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 12

There are four triangular triplets that can be constructed from elements of this array, namely (0, 2, 4), (0, 2, 5), (0, 4, 5), and (2, 4, 5).

Write a function:

function solution(A);

that, given an array A consisting of N integers, returns the number of triangular triplets in this array.

For example, given array A such that:

A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 12

the function should return 4, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [0..1,000];

each element of array A is an integer within the range [1..1,000,000,000].

Solution

Programming language used JavaScript

Time spent on task 4 minutes

Notes

not defined yet

Task timeline

Code: 16:59:34 UTC, js, verify, result: Passed

show code in pop-up

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            var ret = check(A, start, mid, end);
            
            while(end < A.length && ret) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.161 s

Code: 16:59:40 UTC, js, verify, result: Passed

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            var ret = check(A, start, mid, end);
            
            while(end < A.length && ret) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.163 s

expand all User tests

▶

test_data1

✔

0.162 s

OK
function result: 4

Code: 17:00:06 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            var ret = check(A, start, mid, end);
            
            while(end < A.length && ret) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    console.log(arr[base], arr[mid], arr[end]);
    
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.165 s

stdout:

expand all User tests

▶

test_data1

✔

0.166 s

OK
function result: 4

stdout:

3 3 5
3 5 6
3 5 6

Code: 17:01:02 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            var ret = check(A, start, mid, end);
            
            while(end < A.length && ret) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    console.log(arr[base] + '', '+', arr[mid] + '', '>', arr[end] + ' =', arr[base] + arr[mid] > arr[end]);
    
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.168 s

stdout:

1 + 2 > 5 = false
1 + 5 > 8 = false
1 + 8 > 10 = false
1 + 10 > 12 = false
2 + 5 > 8 = false
2 + 8 > 10 = false
2 + 10 > 12 = false
5 + 8 > 10 = true
5 + 10 > 12 = true
8 + 10 > 12 = true

expand all User tests

▶

test_data1

✔

0.169 s

OK
function result: 4

stdout:

3 + 3 > 5 = true
3 + 5 > 6 = true
3 + 5 > 6 = true

Code: 17:01:48 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            var ret = check(A, start, mid, end);
            
            while(end < A.length && ret) {
                end++;
            }
            
            count += end - mid - 1;
            console.log('count:', count);
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    console.log(arr[base] + '', '+', arr[mid] + '', '>', arr[end] + ' =', arr[base] + arr[mid] > arr[end]);
    
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.174 s

stdout:

1 + 2 > 5 = false
count: 0
1 + 5 > 8 = false
count: 0
1 + 8 > 10 = false
count: 0
1 + 10 > 12 = false
count: 0
2 + 5 > 8 = false
count: 0
2 + 8 > 10 = false
count: 0
2 + 10 > 12 = false
count: 0
5 + 8 > 10 = true
count: 2
5 + 10 > 12 = true
count: 3
8 + 10 > 12 = true
count: 4

expand all User tests

▶

test_data1

✔

0.174 s

OK
function result: 4

stdout:

3 + 3 > 5 = true
count: 2
3 + 5 > 6 = true
count: 3
3 + 5 > 6 = true
count: 4

Code: 17:02:38 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            while(end < A.length && check(A, start, mid, end)) {
                end++;
            }
            
            count += end - mid - 1;
            console.log('count:', count);
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    console.log(arr[base] + '', '+', arr[mid] + '', '>', arr[end] + ' =', arr[base] + arr[mid] > arr[end]);
    
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.170 s

stdout:

1 + 2 > 5 = false
count: 0
1 + 5 > 8 = false
count: 0
1 + 8 > 10 = false
count: 0
1 + 10 > 12 = false
count: 0
2 + 5 > 8 = false
count: 0
2 + 8 > 10 = false
count: 0
2 + 10 > 12 = false
count: 0
5 + 8 > 10 = true
5 + 8 > 12 = true
count: 2
5 + 10 > 12 = true
count: 3
8 + 10 > 12 = true
count: 4

expand all User tests

▶

test_data1

✔

0.163 s

OK
function result: 3

stdout:

3 + 3 > 5 = true
3 + 3 > 6 = false
count: 1
3 + 5 > 6 = true
count: 2
3 + 5 > 6 = true
count: 3

Code: 17:02:50 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            while(end < A.length && check(A, start, mid, end)) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    console.log(arr[base] + '', '+', arr[mid] + '', '>', arr[end] + ' =', arr[base] + arr[mid] > arr[end]);
    
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.167 s

stdout:

1 + 2 > 5 = false
1 + 5 > 8 = false
1 + 8 > 10 = false
1 + 10 > 12 = false
2 + 5 > 8 = false
2 + 8 > 10 = false
2 + 10 > 12 = false
5 + 8 > 10 = true
5 + 8 > 12 = true
5 + 10 > 12 = true
8 + 10 > 12 = true

expand all User tests

▶

test_data1

✔

0.178 s

OK
function result: 3

stdout:

3 + 3 > 5 = true
3 + 3 > 6 = false
3 + 5 > 6 = true
3 + 5 > 6 = true

Code: 17:03:04 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            while(end < A.length && check(A, start, mid, end)) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.159 s

expand all User tests

▶

test_data1

✔

0.157 s

OK
function result: 3

Code: 17:03:16 UTC, js, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            while(end < A.length && check(A, start, mid, end)) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

User test case 1:

[3, 3, 5, 6]

Analysis

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.165 s

expand all User tests

▶

test_data1

✔

0.165 s

OK
function result: 3

Code: 17:03:19 UTC, js, final, score: 100

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 4.0.0)
    
    var start = 0;
    var mid = 1;
    var end = 2;
    var count = 0;
    
    if(A.length < 3) {
        return 0;
    }
    
    A.sort(function(a, b) {
        return a-b;
    });
    
    for(start=0; start<A.length-2; start++) {
        for(mid = start+1; mid<A.length-1; mid++) {
            end = mid+1;
            
            while(end < A.length && check(A, start, mid, end)) {
                end++;
            }
            
            count += end - mid - 1;
        }
    }
    
    return count;
}

function check(arr, base, mid, end) {
    if(arr[base] + arr[mid] > arr[end]) return true;
    
    return false;
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N**2)

expand all Example tests

▶

example
example, positive answer, length=6

✔

0.169 s

expand all Correctness tests

▶

extreme_empty
empty sequence + [5,3,3]

✔

0.165 s

▶

extreme_single
1-element sequence + [5,3,3]

✔

0.163 s

0.172 s

▶

extreme_two_elems
2-element sequence + [5,3,3]

✔

0.167 s

0.172 s

▶

extreme_arith_overflow
overflow test, 3 MAXINTs + [5,3,3]

✔

0.169 s

0.167 s

▶

simple

✔

0.164 s

▶

medium1
chaotic sequence of values from [1..100K], length=30

✔

0.168 s

▶

medium2
chaotic sequence of values from [1..1K], length=50

✔

0.168 s

expand all Performance tests

▶

large
chaotic sequence with values from [1..10], length=200

✔

0.179 s

▶

large2
1 followed by an ascending sequence of ~1K elements from [1..2K]

✔

0.341 s

▶

large_random
chaotic sequence of values from [1..1M], length=1K

✔

0.353 s

▶

large_the_same
sequence of the same value value

✔

0.505 s

0.504 s