URAL 1244. Gentlemen(DP)

题目链接

这题不难啊。。。标记一下就行了。表示啥想法也没有。

#include <cstring>
#include <cstdio>
#include <string>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <map>
using namespace std;
#define INF 100000000
int dp[100001];
int flag[100001];
int p[101];
int o[101];
int que[101];
int pre[100001];
int main()
{
    int i,j,n,m;
    scanf("%d%d",&m,&n);
    for(i = 1; i <= n; i ++)
        scanf("%d",&p[i]);
    for(i = 1; i <= m; i ++)
        dp[i] = INF;
    flag[0] = 1;
    for(i = 1; i <= n; i ++)
    {
        for(j = m; j >= p[i]; j --)
        {
            if(dp[j] > dp[j-p[i]] + p[i])
            {
                dp[j] = dp[j-p[i]] + p[i];
                pre[j] = i;
            }
            if(dp[j] == dp[j-p[i]] + p[i])
            {
                flag[j] += flag[j-p[i]];
            }
        }
    }
    if(dp[m] != m)
        printf("0
");
    else if(flag[m] > 1)
        printf("-1
");
    else
    {
        while(m)
        {
            o[pre[m]] = 1;
            m -= p[pre[m]];
        }
        int z = 1;
        for(i = 1; i <= n; i ++)
        {
            if(!o[i])
            {
                if(z)
                {
                    printf("%d",i);
                    z = 0;
                }
                else
                    printf(" %d",i);
            }
        }
    }
    return 0;
}