hdu 1074 doing homework 状态dp

非常好的状态DP 典型的状态DP

// +/- > (<<) > == > |/&

#include <stdio.h>
#include <stack>

using std::stack;
const int INF = 0x3f3f3f3f ;
struct node
{
    char name[105];
    int deadline, time;
}course[17];
struct DP
{
    int point, time, pos, past;
}dp[1<<17];
stack<int> s;
int main()
{
    int cas, i, j, x, n;
    scanf("%d", &cas);
    while( cas-- )
    {
        scanf("%d", &n);
        memset(dp, 0, sizeof(dp));
        for(i=1; i<=n; i++)
            scanf("%s %d %d", course[i].name, &course[i].deadline, &course[i].time);
        int valid = (1<<n)-1 ;
        for(i=1; i<=valid; i++)
        {
            dp[i].point = INF ;
            for(j=n-1; j>=0; j--)  // 控制字典序输出
                if((i | (1<<j)) == i)
                {
                    //time -> cut -> point
                    //past、pos拿来追踪的
                    int pre = i - (1<<j) ;
                    int cut = dp[pre].time + course[j+1].time - course[j+1].deadline;
                    if( cut < 0 ) cut = 0;
                    if( dp[i].point > cut + dp[pre].point )
                    {
                        dp[i].point = cut + dp[pre].point;
                        dp[i].time = dp[pre].time + course[j+1].time;
                        dp[i].pos = j+1;
                        dp[i].past = pre;
                    }
                }
        }
        printf("%d\n", dp[valid].point);
        x = valid;
        while(x!=0)
        {
            s.push(dp[x].pos);
            x = dp[x].past;
        }
        while(!s.empty())
        {
            printf("%s\n", course[s.top()].name);
            s.pop();
        }
    }
    return 0;
}