24 lines
528 B
C++
24 lines
528 B
C++
#include<cstdio>
|
|
#include<cstring>
|
|
int main()
|
|
{
|
|
int n,i,j,b[1001],e[1001],f[1001],ans=0,t;
|
|
scanf("%d",&n);
|
|
for(i=1;i<=n;i++)
|
|
scanf("%d%d",&b[i],&e[i]);
|
|
for(i=1;i<=n-1;i++)
|
|
for(j=i+1;j<=n;j++)
|
|
if (b[i]>b[j])
|
|
{t=b[i];b[i]=b[j];b[j]=t;
|
|
t=e[i];e[i]=e[j];e[j]=t;}
|
|
for(i=1;i<=n;i++)
|
|
f[i]=e[i]-b[i]+1;
|
|
for(i=2;i<=n;i++)
|
|
for(j=1;j<=i-1;j++)
|
|
if (b[i]>e[j]&&f[j]+e[i]-b[i]+1>f[i])
|
|
f[i]=f[j]+e[i]-b[i]+1;
|
|
for(i=1;i<=n;i++)
|
|
if (f[i]>ans) ans=f[i];
|
|
printf("%d",ans);
|
|
}
|
|
|