Test results - Codility

Tasks Details

medium

1. MaxCounters

Calculate the values of counters after applying all alternating operations: increase counter by 1; set value of all counters to current maximum.

Task Score

100%

Correctness

100%

Performance

100%

You are given N counters, initially set to 0, and you have two possible operations on them:

increase(X) − counter X is increased by 1,

max counter − all counters are set to the maximum value of any counter.

A non-empty array A of M integers is given. This array represents consecutive operations:

if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),

if A[K] = N + 1 then operation K is max counter.

For example, given integer N = 5 and array A such that:

A[0] = 3 A[1] = 4 A[2] = 4 A[3] = 6 A[4] = 1 A[5] = 4 A[6] = 4

the values of the counters after each consecutive operation will be:

(0, 0, 1, 0, 0) (0, 0, 1, 1, 0) (0, 0, 1, 2, 0) (2, 2, 2, 2, 2) (3, 2, 2, 2, 2) (3, 2, 2, 3, 2) (3, 2, 2, 4, 2)

The goal is to calculate the value of every counter after all operations.

Assume that the following declarations are given:

struct Results { int * C; int L; // Length of the array };

Write a function:

struct Results solution(int N, int A[], int M);

that, given an integer N and a non-empty array A consisting of M integers, returns a sequence of integers representing the values of the counters.

Result array should be returned as a structure Results.

For example, given:

A[0] = 3 A[1] = 4 A[2] = 4 A[3] = 6 A[4] = 1 A[5] = 4 A[6] = 4

the function should return [3, 2, 2, 4, 2], as explained above.

Write an efficient algorithm for the following assumptions:

N and M are integers within the range [1..100,000];

each element of array A is an integer within the range [1..N + 1].

Solution

Programming language used C

Time spent on task 4 minutes

Notes

not defined yet

Task timeline

Code: 05:23:12 UTC, java, autosave

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// 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");

class Solution {
    public int[] solution(int N, int[] A) {
        // write your code in Java SE 8
    }
}

Code: 05:23:14 UTC, c, autosave

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// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");

struct Results solution(int N, int A[], int M) {
    struct Results result;
    // write your code in C99 (gcc 6.2.0)
    result.C = ...
    result.L = ...
    return result;
}

Code: 05:23:18 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            count = 0;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] > 0){
            arr[A[i] - 1] = 0;
            arr[A[i] - 1] = max;
        }
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:24:40 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;

            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] > 0){
            arr[A[i] - 1] = 0;
            arr[A[i] - 1] = max;
        }
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:24:50 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] > 0){
            arr[A[i] - 1] = 0;
            arr[A[i] - 1] = max;
        }
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:25:49 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] > 0){
            arr[A[i] - 1] = 0;
            arr[A[i] - 1] = max;
        }
        
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:25:59 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] > 0)
            arr[A[i] - 1] = max;
        
        
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:26:11 UTC, c, autosave

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] < max)
            arr[A[i] - 1] = max;
        
        
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Code: 05:26:51 UTC, c, verify, result: Passed

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] < max)
            arr[A[i] - 1] = max;
        
        
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Analysis

expand all Example tests

▶

example
example test

✔

0.001 s

Code: 05:26:53 UTC, c, final, score: 100

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#include <stdlib.h>

void arrInput(int * arr, int num, int len);

struct Results solution(int N, int A[], int M) {
    struct Results result;
    int i, count = 0, max = 0, index = 0, flag = 0;
    int *arr = (int *)malloc(sizeof(int) * N);
    
    result.L = N;
    
    arrInput(arr, 0, N);
    
    for(i = 0; i < M; i++){
        
        if(A[i] > N){
            max = count;
            index = i;
            flag = 1;
            continue;
        }
        
        if(flag == 1 && arr[A[i] - 1] < max)
            arr[A[i] - 1] = max;
        
        
        arr[A[i] - 1]++;
        
    
        if((arr[A[i] - 1]) > count)
            count = arr[A[i] - 1];
            
    }
    
    if(flag == 0)
        result.C = arr;
    else{
        arrInput(arr, max, N);
        for(i = index + 1; i < M; i++)
            arr[A[i] - 1]++;
            
        result.C = arr;
    }
    
    return result;
}

void arrInput(int * arr, int num, int len){
    int i;

    for(i = 0; i < len; i++)
        arr[i] = num;
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N + M)

expand all Example tests

▶

example
example test

✔

0.001 s

expand all Correctness tests

▶

extreme_small
all max_counter operations

✔

0.001 s

▶

single
only one counter

✔

0.001 s

▶

small_random1
small random test, 6 max_counter operations

✔

0.001 s

▶

small_random2
small random test, 10 max_counter operations

✔

0.001 s

expand all Performance tests

▶

medium_random1
medium random test, 50 max_counter operations

✔

0.001 s

▶

medium_random2
medium random test, 500 max_counter operations

✔

0.001 s

▶

large_random1
large random test, 2120 max_counter operations

✔

0.004 s

▶

large_random2
large random test, 10000 max_counter operations

✔

0.008 s

▶

extreme_large
all max_counter operations

✔

0.012 s

0.008 s