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| #include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long LL;
template <class Type>
void read(Type &x)
{
char c;
bool flag = false;
while ((c = getchar()) < '0' || c > '9')
c == '-' && (flag = true);
x = c - '0';
while ((c = getchar()) >= '0' && c <= '9')
x = (x << 3) + (x << 1) + c - '0';
flag && (x = ~x + 1);
}
template <class Type>
void write(Type x)
{
x < 0 && (putchar('-'), x = ~x + 1);
x > 9 && (write(x / 10), 0);
putchar(x % 10 + '0');
}
const int N = 2e5 + 10;
int n, m;
LL tr[N];
struct Swap
{
int x, y;
} s[N];
struct Data
{
int v, s;
} w[N];
void modify (int x, int k)
{
for (x++; x <= m; x += x & -x)
tr[x] += k;
}
LL query (int x)
{
LL res = 0;
for (x++; x; x -= x & -x)
res += tr[x];
return res;
}
int main ()
{
int k;
read(k);
vector <int> ws;
for (int i = 1; i <= k; i++)
{
read(s[i].x), read(s[i].y);
ws.push_back(s[i].x), ws.push_back(s[i].y);
}
sort(ws.begin(), ws.end());
m = ws.erase(unique(ws.begin(), ws.end()), ws.end()) - ws.begin();
for (int i = 0; i < m; i++)
{
w[++n] = (Data){i << 1, i ? ws[i] - ws[i - 1] - 1 : 0};
w[++n] = (Data){i << 1 | 1, 1};
}
m <<= 1;
for (int i = 1; i <= k; i++)
swap(w[lower_bound(ws.begin(), ws.end(), s[i].x) - ws.begin() + 1 << 1], w[lower_bound(ws.begin(), ws.end(), s[i].y) - ws.begin() + 1 << 1]);
LL res = 0;
for (int i = n; i; i--)
{
res += (LL)w[i].s * query(w[i].v);
modify(w[i].v, w[i].s);
}
write(res);
return 0;
}
|