CH模拟赛 皇后游戏

/*
做的时候手推了一下n=2的四种情况，再排一下序就可以了，证明不是很严谨,但我想这就行了，毕竟全是套路
*/
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
#define ll long long
#define fo(i,l,r) for(int i = l;i <= r;i++)
#define fd(i,l,r) for(int i = r;i >= l;i--)
using namespace std;
const int maxn = 100050,N = 100050;
ll read(){
    ll x=0,f=1;
    char ch=getchar();
    while(!(ch>='0'&&ch<='9')){if(ch=='-')f=-1;ch=getchar();};
    while(ch>='0'&&ch<='9'){x=x*10+(ch-'0');ch=getchar();};
    return x*f;
}
struct sb{
    ll a;
    ll b;
}s[N];
int T;
int n,m;
ll cal[N],sum[N];
ll ans = 987654321234500LL;
bool cmp(sb x,sb y){
    return min(x.b,y.a) > min(y.b,x.a);
}
int main(){
    freopen("game.in","r",stdin);
    freopen("game.out","w",stdout);
    T = read();
    while(T--){
        n =read();
        fo(i,1,n) s[i].a = read(),s[i].b = read();
        sort(s+1,s+1+n,cmp);
        cal[1] = s[1].a + s[1].b;
        sum[1] = s[1].a;
        fo(i,2,n){
            sum[i] = sum[i-1] + s[i].a;
            cal[i] = max(cal[i-1],sum[i]) + s[i].b;
        }
        cout<<cal[n]<<endl;
    }
    return 0;
}