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背包问题

#include <iostream>
#include <queue>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string>
#define eps 1e-6
#define IN (1<<28)
using namespace std;
int M,N;
int a[25];
int main()
{
    while( cin >> M )
    {
        cin >> N;
        for( int i = 0; i < N; i++ )
            cin >> a[i];
        int ans = 0;
        int dp[M+5];
        for( int i = 0; i < M+5; i++ )
            dp[i] = IN;
        dp[0] = 0;
        for( int i = 0; i < N; i++ )
        {
            for( int j = M; j >= a[i]; j-- )
            {
                dp[j] = min(dp[j], dp[j-a[i]] + 1);
            }
        }
        if( dp[M] >= 1000 )
            cout << dp[M] << endl;
        else
            cout << "0" << endl;
    }
    return 0;
}

注意初始化即可