NOI OPENJUDGE 1.6(09)

23: Vector dot product calculation

Total time limit : 

1000ms

Memory limit : 

65536kB

describe

In Linear Algebra 、 In Computational Geometry , Vector dot product is a very important operation .

Given two n Dimension vector a=(a1,a2,...,an) and b=(b1,b2,...,bn), Find the dot product a·b=a1b1+a2b2+...+anbn.

Input

The first line is an integer n.1 <= n <= 1000.
The second line contains n It's an integer a1,a2,...,an.
The third line contains n It's an integer b1,b2,...,bn.
Separate adjacent integers with a single space . The absolute value of each integer does not exceed 1000

Output

An integer , That is, the result of the dot product of two vectors .

The sample input

3

1 4 6

2 1 5

Sample output

36

Analysis and code :[ author : Lu changheel ]:

analysis ： Enter the dimension of the vector first , Then input two vectors according to the dimension （ Save in an array ）,

Then calculate the dot product , Just output

Code ：

#include<iostream>

usingnamespace std;

int main()

{

    int a;

    cin >> a;

    int b[1000];

    int c[1000];

    for (int i = 0; i < a; i++)

    {

         cin >> b[i];

    }

    for (int i = 0; i < a; i++)

    {

         cin >> c[i];

    }

    int all = 0;

    for (int i = 0; i < a; i++)

    {

         all = all + b[i] * c[i];

    }

    cout << all;

    return 0;

}