use the greedy algorithm to gain the best benefits

 1. dynamic programming solution

2. greedy algorithm solution 

 

The outputs corresponding to greedy algorithm: 

Input the length of array: 16
  1  6  1  6  2  4  2  1  2  6  7  4  8  7  4  7
max_profit: 25

 corresponding codes:

//step_1 generate a random array with random values
// step_2 suppose the value in array is prices of a specific prices
// step_3 write a function to get your most profit
#include <iostream>
#include <iomanip>
#include <ctime>
#include <cstdlib>
using namespace std;
void generate_array(int *&arr, int len);
void display_array(int arr[], int len);
int greedy_solution(int arr[], int len);
int dp_solution(int arr[], int len);
int main()
{
    srand((unsigned)time(NULL));
    cout << "Input the length of array: ";
    int len;
    cin >> len;
    int *a;
    generate_array(a, len);
    display_array(a, len);
    int max_profit = greedy_solution(a, len);
    //int max_profit = dp_solution(a, len);
    cout << "\nmax_profit: " << max_profit << endl;
    free(a);
    return 0;
}
void generate_array(int *&arr, int len)
{
    arr = new int[len];
    for (int i = 0; i < len; i++){
        arr[i] = rand() % 8 + 1;
    }
}
void display_array(int arr[], int len)
{
    for (int i = 0; i < len; i++) {
        cout << setw(3) << arr[i] ;
    }
}
int greedy_solution(int arr[], int len)
{
    int max_profit = 0;
    for (int i = 1; i < len; i++) {
        if (arr[i] > arr[i-1]){
            max_profit += (arr[i] - arr[i-1]) ;
        }
    }
    return max_profit;
}

The outputs from two different algorithms:

Input the length of array: 5
  8  8  1  7  7
max_profit from greedy_solution : 6
max_profit from dp_solution : 6

The corresponding solutions:

//step_1 generate a random array with random values
// step_2 suppose the value in array is prices of a specific prices
// step_3 write a function to get your most profit
#include <iostream>
#include <iomanip>
#include <ctime>
#include <cstdlib>
using namespace std;
void generate_array(int *&arr, int len);
void display_array(int arr[], int len);
int greedy_solution(int arr[], int len);
int dp_solution(int arr[], int len);
int main()
{
    srand((unsigned)time(NULL));
    cout << "Input the length of array: ";
    int len;
    cin >> len;
    int *a;
    generate_array(a, len);
    display_array(a, len);
    int max_profit_1 = greedy_solution(a, len);
    int max_profit_2 = dp_solution(a, len);
    cout << "\nmax_profit from greedy_solution : " << max_profit_1 << endl;
    cout << "max_profit from dp_solution : " << max_profit_1 << endl;
    free(a);
    return 0;
}
void generate_array(int *&arr, int len)
{
    arr = new int[len];
    for (int i = 0; i < len; i++){
        arr[i] = rand() % 8 + 1;
    }
}
void display_array(int arr[], int len)
{
    for (int i = 0; i < len; i++) {
        cout << setw(3) << arr[i] ;
    }
}
int greedy_solution(int arr[], int len)
{
    int max_profit = 0;
    for (int i = 1; i < len; i++) {
        if (arr[i] > arr[i-1]){
            max_profit += (arr[i] - arr[i-1]) ;
        }
    }
    return max_profit;
}
int dp_solution(int arr[], int len)
{
    int dp_0 = 0;
    int dp_1 = -arr[0];
    for (int i = 1; i < len; i++){
        dp_0 += max(dp_0, dp_1 + arr[i]);
        dp_1 += max(dp_1, dp_0 - arr[i]);
    }
    return dp_0;
}