最优装载问题--贪心算法

#include<iostream>
#include<string>
#include<memory.h>
#include<cstdio>
#include<string>
#include <algorithm>
#define NUM 1001
using namespace std;

int charaNum[NUM] ;//存放输入数据的数组
int tempArr[NUM];

struct load
{
    int weight;
    int index;
}arr[NUM];
int x[NUM];

bool cmp(const load & a, const load & b)
{
    return a.weight<b.weight? true: false;
}

int greedySelect(load * A ,int num,int c)
{
    int sum = 0;
    int cleft = c;
    int i = 0;
    while(i<num && cleft>=A[i].weight)
    {
        cleft-=A[i].weight;
        sum++;
        x[A[i].index] = 1;
        i++;

    }
    return sum;
}

int main()
{
    freopen("in.txt","r",stdin);
    int weight ;
    int num;
    while(cin>>weight>>num)
    {
        memset(x,0 ,sizeof(x));
        for(int i= 0;i<num;i++)
        {
            cin>>arr[i].weight;
            arr[i].index=i;
        }
        stable_sort(arr,arr+num,cmp);
        int sum = greedySelect(arr,num,weight);
        if(sum == 0)
        {
            cout<<"No answer!"<<endl;
        }
        else
        {
            cout<<sum<<endl;
        }
        for(int i = 0;i<num;i++)
        {
            if(x[i] == 1)
            {
                cout<<i+1<<" ";
            }
        }
        cout<<endl;
    }


}

输入：

50 3
40 10 40
37 5
10 30 24 35 40
25 3
30 40 50

输出：

2
1 2
2
1 3
No answer!