You are given a sequence of integers, A1,A2,...,An. And you are allowed a manipulation on the sequence to transform the origin sequence into another sequence B1,B2,...,Bn(Maybe the two sequences are same ). The manipulation is specified as the following three steps:
1.Select an integer Ai and choose an arbitrary positive integer delta as you like.
2.Select some integers Aj satisfying j < i, let's suppose the selected integers are Ak1,Ak2,...,Akt , then subtract an arbitrary positive integer Di from Aki (1 ≤ i ≤ t) as long as sum(Di) = delta.
3.Subtract delta from Ai.
The manipulation can be performed any times. Can you find a way to transform A1,A2,...,An to B1,B2,...,Bn ?
Input
The input consist of multiple cases. Cases are about 100 or so. For each case, the first line contains an integer N(1 ≤ N ≤ 10000) indicating the number of the sequence. Then followed by N lines, ith line contains two integers Ai and Bi (0 ≤ Bi ≤ Ai ≤ 4294967296).
Output
Output a single line per case. Print "YES" if there is a certain way to transform Sequence A into Sequence B. Print "NO" if not.
Sample Input
3 3 2 4 2 5 2 3 2 0 7 1 3 1
Sample Output
YES NO
#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
int max(int x,int y)
{
if(x>y)
return x;
else
return y;
}
int main()
{
long long maxn,a[10000],b[10000],sum,q;
int t,i;
while(~scanf("%d",&t))
{
sum=maxn=0;
for(i=0;i<t;i++)
{
scanf("%lld%lld",&a[i],&b[i]);
q=a[i]-b[i];
sum+=q;
maxn=max(maxn,q);
}
if(sum%2!=0)
printf("NO
");
else if(2*maxn>sum)
printf("NO
");
else
printf("YES
");
}
return 0;
}
/*
6
10 1
5 3
16 5
9 3
9 2
14 1
*/