2015 ACM/ICPC Asia Regional Shanghai Online 1010题

[题目链接]
(http://acm.hdu.edu.cn/contests/contest_showproblem.php?pid=1010&cid=623)
题目描述：
A Sweet Journey

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 2619 Accepted Submission(s): 1007

Problem Description
Master Di plans to take his girlfriend for a travel by bike. Their journey, which can be seen as a line segment of length L, is a road of swamps and flats. In the swamp, it takes A point strengths per meter for Master Di to ride; In the flats, Master Di will regain B point strengths per meter when riding. Master Di wonders：In the beginning, he needs to prepare how much minimum strengths. (Except riding all the time,Master Di has no other choice)

Input
In the first line there is an integer t (1≤t≤50), indicating the number of test cases.
For each test case:
The first line contains four integers, n, A, B, L.
Next n lines, each line contains two integers: Li,Ri, which represents the interval [Li,Ri] is swamp.
1≤n≤100,1≤L≤105,1≤A≤10,1≤B≤10，1≤Li

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

bool flag[100010];

int main()
{
    int T,n,a,b,R;
    int l,r;
    cin>>T;
    int k=1;
    while(T--)
    {
        scanf("%d%d%d%d",&n,&a,&b,&R);
        memset(flag,false,sizeof(flag));
        while(n--)
        {
            scanf("%d%d",&l,&r);
            for(int i=l;i<=r-1;i++)
            {
                flag[i]=true;
            }
        }
        int ans,min;
        ans=0;
        min=0xfffffff;
        for(int  i=0;i<R;i++)
        {
            if(flag[i]==false)
            {
                ans+=b;
            }
            else if(flag[i]==true)
            {
                ans-=a;
            }
            if(ans<min)
            {
                min=ans;
            }
        }
        if(min>=0)
        printf("Case #%d: 0\n",k++);//特别注意，min>=0时，输出0即可
        else
        {
            printf("Case #%d: %d\n",k++,-min);
        }
    }
    return 0;
}