HDU 2141 Can you find it? (二分)

题目链接:

Can you find it?

Time Limit: 10000/3000 MS (Java/Others)    Memory Limit: 32768/10000 K (Java/Others)
Total Submission(s): 38634    Accepted Submission(s): 9395

Problem Description
Give you three sequences of numbers A, B, C, then we give you a number X. Now you need to calculate if you can find the three numbers Ai, Bj, Ck, which satisfy the formula Ai+Bj+Ck = X.
 
Input
There are many cases. Every data case is described as followed: In the first line there are three integers L, N, M, in the second line there are L integers represent the sequence A, in the third line there are N integers represent the sequences B, in the forth line there are M integers represent the sequence C. In the fifth line there is an integer S represents there are S integers X to be calculated. 1<=L, N, M<=500, 1<=S<=1000. all the integers are 32-integers.
 
Output
For each case, firstly you have to print the case number as the form "Case d:", then for the S queries, you calculate if the formula can be satisfied or not. If satisfied, you print "YES", otherwise print "NO".
 
Sample Input
3 3 3
1 2 3
1 2 3
1 2 3
3
1
4
10
 
Sample Output
Case 1:
NO
YES
NO
 
Author
wangye
 
Source
 

题目大意:

多组数据输入

第一行是三个序列各自元素的个数

第2,3,4是三个序列

第4行是x的个数

下面的x行是多种情况的x值

分析:

三个序列三个数组,把前面两个数组组合为一个数组

比如1 2 3,1 2 3,这两个序列组合为一个数组‘

1+1,1+2,1+3,2+1,2+2,2+3,3+1,3+2,3+3,

计算一下就是

2,3,4,3,4,5,4,5,6,有重复的但是不用去掉,称这个序列为t

然后与第三个序列组合

1 ,2,3,(第三个序列)

然后将t序列升序排序,t与第三个序列组合的时候,t序列采用二分寻找数据

注意点:

1.不能采用set去重,不然会超内存(第一次遇到超内存,好激动啊啊啊啊啊)

2.对t序列不能采用for循环寻找数据,要采用排好序之后再二分查找数据,不然会超时

代码如下:

#include<bits/stdc++.h>
using namespace std;
bool cmp(int a,int b)
{
return a<b;
}
int main()
{
int n1,n2,n3,n=;
while(~scanf("%d %d %d",&n1,&n2,&n3))
{
int a[n1],b[n2],c[n3];
for(int i=; i<n1; i++)
{
scanf("%d",&a[i]);
}
for(int j=; j<n2; j++)
{
scanf("%d",&b[j]);
}
for(int k=; k<n3; k++)
{
scanf("%d",&c[k]);
}
int xn;
int t[n1*n2];
scanf("%d",&xn);
int x[xn];
for(int i=; i<xn; i++)
{
scanf("%d",&x[i]);
}
int y=;
for(int i=; i<n1; i++)
{
for(int j=; j<n2; j++)
{
int z=a[i]+b[j];
t[y]=z;
y++;
}
}
sort(t,t+(n1*n2),cmp);
printf("Case %d:\n",n);
for(int i=; i<xn; i++)
{
int f=;
for(int k=;k<n3;k++)
{
int l=,h=n1*n2-;
while(l<=h)
{
int mid=(l+h)/; if(t[mid]==x[i]-c[k])
{
f=;
break;
}else if(t[mid]>x[i]-c[k])
{
h=mid-;
}else if(t[mid]<x[i]-c[k])
{
l=mid+;
}
}
if(f==)
break;
}
if(f==)
{
printf("YES\n");
}
else
{
printf("NO\n");
}
}
n++;
}
return ;
}

哈哈哈哈哈哈哈哈哈哈

今天真的是超级开心

不准吐槽。。。。。

。。。。。。。。。。

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