解题思路

比较简单，考察快排。C++选手的快乐sort。
假设一个是x一个是y，问有几台电脑x，y都比某一台电脑小。
先对x降序排序，再把第一个电脑的y记位最大值，康康会不会比后一个人大，大就计数，否则修改最大值即可。

#include <bits/stdc++.h>
#pragma GCC optimize(2)
#pragma GCC optimize(3)
using namespace std;
#define js ios::sync_with_stdio(false);cin.tie(0); cout.tie(0)
typedef long long ll;
const ll MOD = 1e9 + 7;
inline ll read() { ll s = 0, w = 1; char ch = getchar(); while (ch < 48 || ch > 57) { if (ch == '-') w = -1; ch = getchar(); }    while (ch >= 48 && ch <= 57) s = (s << 1) + (s << 3) + (ch ^ 48), ch = getchar();    return s * w; }
inline void write(ll x) { if (!x) { putchar('0'); return; } char F[200]; ll tmp = x > 0 ? x : -x; if (x < 0)putchar('-');    int cnt = 0;    while (tmp > 0) { F[cnt++] = tmp % 10 + '0';        tmp /= 10; }    while (cnt > 0)putchar(F[--cnt]); }
inline ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
ll qpow(ll a, ll b) { ll ans = 1;    while (b) { if (b & 1)    ans *= a;        b >>= 1;        a *= a; }    return ans; }    ll qpow(ll a, ll b, ll mod) { ll ans = 1; while (b) { if (b & 1)(ans *= a) %= mod; b >>= 1; (a *= a) %= mod; }return ans % mod; }
inline int lowbit(int x) { return x & (-x); }

const int N = 1e5 + 7;
struct Node {
    int x, y;
    bool operator <(const Node& b)const {
        return x > b.x;
    }
}a[N];

int main() {
    int n = read();
    for (int i = 1; i <= n; ++i)    a[i].x = read(), a[i].y = read();
    sort(a + 1, a + 1 + n);
    int cnt = 0, maxi = a[1].y;
    for (int i = 2; i <= n; ++i)
        if (a[i].y < maxi)    ++cnt;
        else    maxi = a[i].y;
    write(cnt), putchar(10);
    return 0;
}