机器学习：最近邻规则KNN算法

这个算法就比较简单易懂了

就是把每个向量的特征值抽象成坐标，寻找最近的k个点，来进行划分

代码如下

#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;
typedef vector<double> Vd;
const int maxn = 1111;
Vd V[maxn], Vt;
struct Date
{
    int lab;
    double v;
    bool operator <(const Date &B) const
    { return v < B.v; }
}a[maxn];
int lab[maxn], T[maxn];
double Distance(Vd A, Vd B)
{
    double ans = 0;
    for(int i = 0; i < A.size(); i++)
        ans += (A[i] - B[i])*(A[i] - B[i]);
    return ans;
}
int n, m, k;
double x;
int main()
{
    cin>>n>>m;
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cin>>x;
            V[i].push_back(x);
        }
        cin>>x; lab[i] = x;
    }
    for(int i = 0; i < m; i++)
        cin>>x, Vt.push_back(x);
    for(int i = 0; i < n; i++)
    {
        a[i].lab = lab[i];
        a[i].v = Distance(V[i], Vt);
    }
    sort(a, a+n);
    int ans, ansv = 0;
    for(int i = 0; i < k; i++)
        if(++T[a[i].lab] > ansv)
            ans = a[i].lab, ansv = T[a[i].lab];
    cout<<ans<<endl;
}