Codility練習 MaxCounters

vector<int> solution(int N, vector<int> &A) {
    // write your code in C++14 (g++ 6.2.0)
    int max = 0;
    int lastmax = 0;
    vector<int>res(N);
    for(int i : A)
    {
        if(i>=1&& i<=N)
        {
            if( res[i-1] < lastmax )
            {
                res[i-1] = lastmax + 1;
            }
            else
            {
                res[i-1] ++;
            }
            
            if(res[i-1] > max)
            {
                max = res[i-1];
            }
        }
        else if(i == N+1)
        {
           lastmax = max;  
        }
    }
    
    for(int i = 0; i < N; i++)
    {
        if(res[i] < lastmax )
        {
            res[i] = lastmax;
        }
    }
    
    
    return res;
}

問題描述

 

Task description

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.

Write a function:

vector<int> solution(int N, vector<int> &A);

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 vector of integers.

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].