你是打算让我猜变量的意思？？
by liqingyang @ 2020-03-01 15:26:57
@[SylviaFang](/user/289130) 用我的思路试试（好久以前写的）：
```cpp
// luogu-judger-enable-o2
#include <stdio.h>
int main(){
int l,m,start,stop,count=0;
scanf("%d%d",&l,&m);
int a[l+1];
for(int i=0;i<=l;i++){
a[i]=1;
}
for(int i=0;i<m;i++){
scanf("%d%d",&start,&stop);
for(int j=start;j<=stop;j++){
a[j]=0;
}
}
for(int i=0;i<=l;i++){
if(a[i]!=0){
count++;
}
}
printf("%d",count);
return 0;
}
```
by BlueSu @ 2020-03-01 15:28:06
怎么不试试我的（个人认为较短）：
```cpp
#include<iostream>
using namespace std;
bool a[10010];
int main()
{
int l,m,ans=0;
cin>>l>>m;
for(int i=1;i<=m;i++)
{
int a1,a2;
cin>>a1>>a2;
for(int j=a1;j<=a2;j++)
{
a[j]=1;
}
}
for(int i=0;i<=l;i++)
{
ans+=!a[i];
}
cout<<ans<<endl;
return 0;
}
```
by liqingyang @ 2020-03-01 15:29:42
个人认为很短
```cpp
#include <iostream>
using namespace std;
bool a[10000+10];
int main(){
int n,m,x,y,ans=0;
cin >> n >> m;
for (int i=0;i<m;i++){
cin >> x >> y;
for (int j=x;j<=y;j++){
a[j]=1;
}
}
for (int i=0;i<=n;i++){
if (!a[i]) ans++;
}
cout << ans << endl;
return 0;
}
```
by HearTheWindSing @ 2020-03-01 15:31:10
@[wangyxhaha](/user/177072) 来看看[这个](https://www.luogu.com.cn/discuss/show/196746)呗
by liqingyang @ 2020-03-01 15:34:41
@[liqingyang](/user/272088) emmmm对不起，没做过QAQ
by HearTheWindSing @ 2020-03-01 15:38:24
没关系
by liqingyang @ 2020-03-01 15:39:03
@[liqingyang](/user/272088) 我年龄比你还大，学的时间比你还长，但是不能像你一样爆切蓝题QAQ
by HearTheWindSing @ 2020-03-01 15:43:39
个人认为最短
```
#include<bits/stdc++.h>
using namespace std;
int main()
{
int i,j,a[10010]={0},m,l,b,e,sum=0;
cin>>l>>m;
for(i=1;i<=m;++i){
cin>>b>>e;
for(j=b;j<=e;++j)
a[j]=1;
}
for(i=0;i<=l;++i)
if(a[i]==0)sum++;
cout<<sum;
}
```
by Kevin施黄凯 @ 2020-03-09 15:06:18
~~个人认为很短~~
**其实很长**
```cpp
#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
int a[10001];
void dfs(int x,int y){
for(int i=x;i<=y;i++){
if(a[i])a[i]=0;
}
return;
}
int bfs(int x){
int s=0;
for(int i=0;i<=x;++i)
if(a[i])s++;
return s;
}
int main(){
int m,l,s,x,y;
cin>>l>>m;
memset(a,1,sizeof(a));
for(int i=1;i<=m;i++){
cin>>x>>y;
dfs(x,y);
}
s=bfs(l);
cout<<s;
return 0;
}
```
by _SHM_ @ 2020-03-15 12:41:15