AGC028. Problem C

agc028_c.cpp

#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define all(x) (x).begin(), (x).end()
using namespace std;
typedef long long ll;
typedef long double ld;
int n, A[100010], B[100010], P[100010][2];
ll s[200010];
vector<pair<int,int> > v;
int main() {
	memset(P, -1, sizeof(P));
	scanf("%d", &n);
	ll r1 = 0, r2 = 0;
	for(int i=1; i<=n; i++) {
		scanf("%d%d", A+i, B+i);
		r1 += A[i]; r2 += B[i];
		v.push_back({A[i], i});
		v.push_back({B[i], i});
	}
	sort(all(v));
	for(int i=0; i<sz(v); i++) {
		s[i] += v[i].first;
		s[i+1] += s[i];
		if(P[v[i].second][0] == -1) P[v[i].second][0] = i;
		else P[v[i].second][1] = i;
	}
	ll r = min(r1, r2);
	for(int i=1; i<=n; i++) {
		ll val = 0;
		if(n == 2);
		else if(n-3 < P[i][0]) val = s[n-3];
		else if(n-3 >= P[i][1]) val = s[n-1] - A[i] - B[i];
		else if(n-2 == P[i][1]) val = s[n-1] - A[i] - B[i];
		else val = s[n-2] - v[P[i][0]].first;
		r = min(r, val + A[i] + B[i]);
	}
	printf("%lld", r);
	return 0;
}