csu 1603: Scheduling the final examination（贪心）

1603: Scheduling the final examination

Time Limit: 10 Sec  Memory Limit: 128 MB
Submit: 43  Solved: 12
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Description

For the most of the university students，what they most want is that they can obtain 60 points from the final examination of every subject. Now, final examination is coming. As an excellent programmer，you are asked for help. The full mark is 100, and it is need greater than or equal to 60 to pass subjects. Given the description of every subject, you should schedule the time of review to every subject in order to pass every subject and at the same time to obtain the higher total scores as possible.

Input

The input consists of multiple test cases. For each test case, the first line is an integer n (1<=n<=50), which is the number of subjects. Then n lines follow, each line has four integers si, ti, ai, di to describe the subject. si(0<=si<=100)：the score that he can obtained without reviewing，ti(1<=ti<720)：the time of examination，
ai(1<=ai<=40)：the first hour reviewing on this subject will improve ai scores，di(0<=di<=4)：the improving scores will decrease di every reviewing hour. For example，when ai = 10, di = 2, the first hour viewing will improve 10 scores , and the second hour viewing will only improve 8 scores.

Output

For each test case, to output in one line. If he can pass all the subjects, please output an integer which is the highest total scores, otherwise please output a string “you are unlucky”.

Sample Input

158 3 5 3158 1 5 3440 6 10 250 9 10 260 3 4 270 1 4 2442 6 10 250 9 10 254 3 4 270 1 4 2430 6 10 250 9 10 254 3 4 270 1 4 2

Sample Output

6563280274you are unlucky

题意不再赘述

先让所有考试的分数都能到达60  然后选取当前a值最大的考试进行复习。。。

#include<cstdio>#include<cstdlib>#include<iostream>#include<cstring>#include<cmath>#include<algorithm>#include<queue>#include<vector>#include<set>#include<map>using namespace std;#define REP(x, y) for(int x = 0; x < y; x++)#define DWN(x, y) for(int x = y-1; x > -1; x--)struct Exam{    int s,t,a,d;    int add()    {        if(100-s>a) return a;        else return 100-s;    }}ex[60]; int timer[750]; int main(){//    freopen("D.in", "r", stdin);    int n;    while(scanf("%d",&n)!=EOF)    {        int mx=-1;        memset(timer,0,sizeof timer);        for(int i=0;i<n;i++)        {            scanf("%d%d%d%d",&ex[i].s,&ex[i].t,&ex[i].a,&ex[i].d);            mx=max(mx,ex[i].t);            int t=ex[i].t;            while(t>0&&ex[i].s<60&&ex[i].a>0)            {                if(timer[t]==0)                {                    ex[i].s+=ex[i].add();                    ex[i].a-=ex[i].d;                    timer[t]=1;                }                t--;            }         }        for(int i=720;i>0;i--)        {            if(!timer[i])            {                int m=-1;                for(int j=0;j<n;j++)                {                    if(ex[j].t>=i&&(m==-1||ex[m].add()<ex[j].add()))                        m=j;                }                if(m!=-1&&ex[m].a>0)                {                    ex[m].s+=ex[m].add();                    ex[m].a-=ex[m].d;                }            }        }        int ans=0;        int flag=1;        for(int i=0;i<n;i++)        {            if(ex[i].s>=60)                ans+=ex[i].s;            else            {                flag=0; break;            }        }        if(flag)            printf("%d\n",ans);        else puts("you are unlucky");    }    return 0;}  /**************************************************************    Problem: 1603    User: youngkl    Language: C++    Result: Accepted    Time:8 ms    Memory:1488 kb****************************************************************/