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hdu 5059 Help him

2024-07-25 18:03:14   216人阅读

Help him

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 480    Accepted Submission(s): 119


Problem Description
As you know, when you want to hack someone‘s program, you must submit your test data. However sometimes you will submit invalid data, so we need a data checker to check your data. Now small W has prepared a problem for BC, but he is too busy to write the data checker. Please help him to write a data check which judges whether the input is an integer ranged from a to b (inclusive).
Note: a string represents a valid integer when it follows below rules.
1. When it represents a non-negative integer, it contains only digits without leading zeros.
2. When it represents a negative integer, it contains exact one negative sign (‘-‘) followed by digits without leading zeros and there are no characters before ‘-‘.
3. Otherwise it is not a valid integer.
 

Input
Multi test cases (about 100), every case occupies two lines, the first line contain a string which represents the input string, then second line contains a and b separated by space. Process to the end of file.

Length of string is no more than 100.
The string may contain any characters other than ‘\n‘,‘\r‘.
-1000000000$\leq a \leq b \leq 1000000000$
 

Output
For each case output "YES" (without quote) when the string is an integer ranged from a to b, otherwise output "NO" (without quote).
 

Sample Input
10
-100 100
1a0
-100 100
 

Sample Output
YES
NO
 

Source
BestCoder Round #12
 


题解及代码：


       题意很简单，给一个字符串，和一个区间，看这个字符串能否构成一个合法的整数，并且其值是否在这个区间内（注意-0为非法数据）。

       首先直接排除-和-0的情况，然后判断前导0的情况，再判断0-9以外字符的情况，接着看其长度是否大于12，最后把它转化成整数，判断大小。

     

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <map>
using namespace std;
typedef long long ll;


bool judge(char s[],ll a,ll b)
{
    ll num=0,d=1,i=0;
    int len=strlen(s),k=0;
    if(s[0]=='-') d=-1,k++;
    if(k==len||s[0]=='-'&&s[k]=='0') return false;
    for(i=k;i<len-1;i++)
    if(s[i]!='0') break;

    if(i!=k) return false;
    for(int i=k;i<len;i++)
    if(s[i]<'0'||s[i]>'9') return false;

    for(int i=k;i<len;i++)
    {
        num=num*10+s[i]-'0';
        if(i-k>11) return false;
    }
    //printf("%I64d\n",num*d);
    if(num*d<a||num*d>b)  return false;
    return true;
}

int main()
{
    ll a,b;
    char s[110];
    while(gets(s)!=NULL)
    {
       scanf("%I64d%I64d",&a,&b);
       if(a>b) swap(a,b);

       if(judge(s,a,b)) printf("YES\n");
       else printf("NO\n");
       getchar();
    }
    return 0;
}






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