Language: C++

#include <bits/stdc++.h>
using namespace std;

#define ms(s, n) memset(s, n, sizeof(s))
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define FORd(i, a, b) for (int i = (a) - 1; i >= (b); i--)
#define FORall(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define sz(a) int((a).size())
#define present(t, x) (t.find(x) != t.end())
#define all(a) (a).begin(), (a).end()
#define uni(a) (a).erase(unique(all(a)), (a).end())
#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define prec(n) fixed<<setprecision(n)
#define bit(n, i) (((n) >> (i)) & 1)
#define bitcount(n) __builtin_popcountll(n)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<pi> vii;
const int MOD = (int) 1e9 + 7;
const int MOD2 = 1007681537;
const int INF = (int) 1e9;
const ll LINF = (ll) 1e18;
const ld PI = acos((ld) -1);
const ld EPS = 1e-9;
inline ll gcd(ll a, ll b) {ll r; while (b) {r = a % b; a = b; b = r;} return a;}
inline ll lcm(ll a, ll b) {return a / gcd(a, b) * b;}
inline ll fpow(ll n, ll k, int p = MOD) {ll r = 1; for (; k; k >>= 1) {if (k & 1) r = r * n % p; n = n * n % p;} return r;}
template<class T> inline int chkmin(T& a, const T& val) {return val < a ? a = val, 1 : 0;}
template<class T> inline int chkmax(T& a, const T& val) {return a < val ? a = val, 1 : 0;}
inline ll isqrt(ll k) {ll r = sqrt(k) + 1; while (r * r > k) r--; return r;}
inline ll icbrt(ll k) {ll r = cbrt(k) + 1; while (r * r * r > k) r--; return r;}
inline void addmod(int& a, int val, int p = MOD) {if ((a = (a + val)) >= p) a -= p;}
inline void submod(int& a, int val, int p = MOD) {if ((a = (a - val)) < 0) a += p;}
inline int mult(int a, int b, int p = MOD) {return (ll) a * b % p;}
inline int inv(int a, int p = MOD) {return fpow(a, p - 2, p);}
inline int sign(ld x) {return x < -EPS ? -1 : x > +EPS;}
inline int sign(ld x, ld y) {return sign(x - y);}
#define db(x) cerr << #x << " = " << (x) << " ";
#define endln cerr << "\n";

const int maxn = 1e6 + 5;
int n;
int x[maxn];
int y[maxn];
int z[2];
int t[2];

int fen[maxn];

void upd(int p, int val) {
    p++;
    for (; p < maxn; p += p & -p) {
        chkmax(fen[p], val);
    }
}

int query(int p) {
    p++;
    int res = 0;
    for (; p > 0; p -= p & -p) {
        chkmax(res, fen[p]);
    }
    return res;
}

void solve() {
    FOR(i, 0, 2) cin >> z[i] >> t[i];
    cin >> n;
    FOR(i, 0, n) cin >> x[i] >> y[i];
    long long ans = (long long) (abs(z[0] - z[1]) + abs(t[0] - t[1])) * 100;
    if (z[0] > z[1]) {
        swap(z[0], z[1]);
        swap(t[0], t[1]);
    }
    if (t[0] > t[1]) {
        t[0] *= -1, t[1] *= -1;
        FOR(i, 0, n) y[i] *= -1;
    }
    vii v;
    FOR(i, 0, n) {
        if (x[i] >= z[0] && x[i] <= z[1] && y[i] >= t[0] && y[i] <= t[1]) {
            v.pb(mp(x[i], y[i]));
        }
    }
    sort(all(v));
    n = sz(v);
    vi dc;
    FOR(i, 0, sz(v)) {
        x[i] = v[i].fi;
        y[i] = v[i].se;
        dc.pb(x[i]);
        dc.pb(y[i]);
    }
    sort(all(dc)), uni(dc);
    if (z[0] == z[1] || t[0] == t[1]) {
        cout << prec(15) << tmp + (long double) n * (10 * PI - 20) << "\n";
        return;
    }
    int x = 0;
    FOR(i, 0, n) {
        int iy = lower_bound(all(dc), y[i]) - dc.begin();
        int mx = query(iy);
        upd(iy, mx + 1);
        chkmax(x, mx);
    }
    if (x < min(z[1] - z[0], t[1] - t[0]) + 1) {
        cout << prec(15) << ans - (long double) x * (20 - 10 * PI / 2) << "\n";
    }
    else {
        cout << prec(15) << ans - (long double) (x - 1) * (20 - 10 * PI / 2) + (10 * PI - 20) << "\n";
    }
}

int main() {
    int JUDGE_ONLINE = 1;
    if (fopen("in.txt", "r")) {
        JUDGE_ONLINE = 0;
        assert(freopen("in.txt", "r", stdin));
        //assert(freopen("out.txt", "w", stdout));
    }
    else {
        ios_base::sync_with_stdio(0), cin.tie(0);
    }
    solve();
    if (!JUDGE_ONLINE) {
        //cout << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    }
    return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:103:29: error: 'tmp' was not declared in this scope; did you mean 'tm'?
  103 |         cout << prec(15) << tmp + (long double) n * (10 * PI - 20) << "\n";
      |                             ^~~
      |                             tm