R13541444819 @ 2023-04-02 22:36:54
import java.util.*;
public class Main{
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
int l = scan.nextInt() + 1;
int m = scan.nextInt();
int arr[] = new int[2 * m];
for (int i = 0; i < arr.length; i++){
arr[i] = scan.nextInt();
}
for (int i = 2; i < arr.length; i = i + 2) {
if (arr[i] < arr[0] && arr[i + 1] > arr[0] && arr[i + 1] < arr[1]){
arr[0] = arr[i];
}else if (arr[i] >arr[0] && arr[i] < arr[1] && arr[i + 1] > arr[1]) {
arr[1] = arr[i + 1];
}else{
continue;
}
arr[i] = arr[i + 1] = 0;
}
int sum = 0;
for (int i = 1; i < arr.length; i = i + 2){
if (arr[i] == 0) {
continue;
}
sum += arr[i] - arr[i - 1] + 1;
}
System.out.println(l - sum);
}
}by a15244412002 @ 2023-04-16 20:20:56
AC
#include<iostream>
using namespace std;
int main(){
int l,m,start,end,a[100000],ans=0;
cin>>l>>m;
for(int i=0;i<=l;i++){
a[i]=1;
}//0可种树//遍历
for(int i=1;i<=m;i++){
cin>>start>>end;
if(start==1&&end==l){
cout<<"0";
return 0;
}//不加第一个不AC
for(int j=start;j<=end;j++){
a[j]=0;
}//可以重复拔
}
for(int i=0;i<=l;i++){
if(a[i]==1){
ans++;
}
}//累加
cout<<ans;
//cout is 298
//----wrong----
/*for(int i=1;i<=l;i++){
a[i]=1;
}
for(int i=1;i<=m;i++){
cin>>start>>end;
for(int j=start;j<=end;j++){
a[j]=0;
}
}
for(int i=1;i<=l;i++){
if(a[i]==1){
ans++;
}
}
cout<<ans;*/
//cout is 297
return 0;
}