算法笔记

给定n个数，以及数k，判断是否能够从n个数中找出任意个数，使其和等于k 

#include<iostream>
#include<malloc.h>
using namespace std;
int sum_out;
int *a;
int max;
bool dfs(int i,int sum){
    


    if (i == max) return sum == sum_out;

    if (dfs(i + 1, sum))return true;


    if (dfs(i + 1, sum + a[i])) return true;

    return false;

    

}
int main(){
    cout << "max=";
    cin >> max;
    cout << endl;
    cout << "sum=";
    cin >> sum_out;
    cout << endl;
    a = (int *)malloc(sizeof(int)*max);

    for (int i = 0; i < max; i++){
        cin >> a[i];
    }

    if (dfs(0, 0)) printf("yes
");
    else
        printf("no
");
    free(a);
    system("PAUSE");
    return 0;
}