Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

Code mẫu của ladpro98

#include <bits/stdc++.h>

const int N = 100005;
const double INF = 1e18;

using namespace std;

int n; long long p[N], v[N];
double res;

double F(double t) {
  double mi = INF, ma = -INF, pos;
  for(int i = 1; i <= n; i++) {
    pos = t * v[i] + p[i];
    mi = min(mi, pos);
    ma = max(ma, pos);
  }
  return ma - mi;
}

int main() {
  ios::sync_with_stdio(0); cin.tie(0);
  cin >> n;
  for(int i = 1; i <= n; i++) cin >> p[i];
  for(int i = 1; i <= n; i++) cin >> v[i];
  double l = 0, r = INF, tl, tr, fl, fr; res = INF;
  for (int step = 0; step < 500; ++step) {
    tl = l + (r - l) / 3;
    tr = r - (r - l) / 3;
    fl = F(tl); fr = F(tr);
    res = min(res, min(fl, fr));
    if (fl < fr) r = tr; else l = tl;
  }
  cout << setprecision(3) << fixed << res / 2 << endl;
  return 0;
}

Code mẫu của RR

#include <sstream>
#include <iomanip>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <string>
#include <deque>
#include <complex>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define FORN(i,a,b) for(int i=(a),_b=(b);i<_b;i++)
#define DOWN(i,a,b) for(int i=a,_b=(b);i>=_b;i--)
#define SET(a,v) memset(a,v,sizeof(a))
#define sqr(x) ((x)*(x))
#define ll long long
#define F first
#define S second
#define PB push_back
#define MP make_pair

#define DEBUG(x) cout << #x << " = "; cout << x << endl;
#define PR(a,n) cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl;
#define PR0(a,n) cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl;
using namespace std;

//Buffer reading
int INP,AM,REACHEOF;
const int BUFSIZE = (1<<12) + 17;
char BUF[BUFSIZE+1], *inp=BUF;
#define GETCHAR(INP) { \
    if(!*inp && !REACHEOF) { \
        memset(BUF,0,sizeof BUF);\
        int inpzzz = fread(BUF,1,BUFSIZE,stdin);\
        if (inpzzz != BUFSIZE) REACHEOF = true;\
        inp=BUF; \
    } \
    INP=*inp++; \
}
#define DIG(a) (((a)>='0')&&((a)<='9'))
#define GN(j) { \
    AM=0;\
    GETCHAR(INP); while(!DIG(INP) && INP!='-') GETCHAR(INP);\
    if (INP=='-') {AM=1;GETCHAR(INP);} \
    j=INP-'0'; GETCHAR(INP); \
    while(DIG(INP)){j=10*j+(INP-'0');GETCHAR(INP);} \
    if (AM) j=-j;\
}
//End of buffer reading

const long double PI = acos((long double) -1.0);
const int MN = 100111;

int n, a[MN], v[MN];
long double x[MN];

long double get(long double t) {
    FOR(i,1,n) x[i] = a[i] + v[i] * t;
    return *max_element(x+1, x+n+1) - *min_element(x+1, x+n+1);
}

void duyet() {
    long double res = *max_element(a+1, a+n+1) - *min_element(a+1, a+n+1);

    FOR(i,1,n) FOR(j,1,n) {
        if (v[j] == v[i]) continue;
        long double t = (a[i] - a[j]) / (long double) (v[j] - v[i]);

        if (t < 0) continue;

        res = min(res, get(t));
    }
    if (abs(res) < 1e-6) res = 0.0;
    cout << (fixed) << setprecision(3) << res / 2.0 << endl;
}

long double range(long double l, long double r, int MAX_TURN = 200) {
    long double res = 1e100;
    res = min(res, get(r));
    REP(turn,MAX_TURN) {
        long double x1 = (l*2 + r) / 3.0;
        long double x2 = (l + r*2) / 3.0;
        long double y1 = get(x1), y2 = get(x2);

        res = min(res, min(y1, y2));

        if (y1 < y2) r = x2;
        else l = x1;
    }
    return res;
}

void solve() {
    long double res = *max_element(a+1, a+n+1) - *min_element(a+1, a+n+1);
    res = min(res, range(0, 1e10));
    if (res < 0) res = 0;
    if (abs(res) < 1e-6) res = 0.0;
    cout << (fixed) << setprecision(3) << res / 2.0 << endl;
}

int main() {
    scanf("%d", &n);
    FOR(i,1,n) scanf("%d", &a[i]);
    FOR(i,1,n) scanf("%d", &v[i]);

    if (n <= 100) duyet(); else solve();
    return 0;
}

Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>

#include <ctime>
#include <deque>
#include <bitset>
#include <cctype>
#include <utility>
#include <cassert>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(int i = 0; i < (n); ++i)
#define Repd(i,n) for(int i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(int i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(int i = (a); i >= (b); --i)
//#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
//#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))

template<class F, class T> T convert(F a, int p = -1) { stringstream ss; if (p >= 0) ss << fixed << setprecision(p); ss << a; T r; ss >> r; return r; }
template<class T> T gcd(T a, T b) { T r; while (b != 0) { r = a % b; a = b; b = r; } return a; }
template<class T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template<class T> T sqr(T x) { return x * x; }
template<class T> T cube(T x) { return x * x * x; }
template<class T> int getbit(T s, int i) { return (s >> i) & 1; }
template<class T> T onbit(T s, int i) { return s | (T(1) << i); }
template<class T> T offbit(T s, int i) { return s & (~(T(1) << i)); }
template<class T> int cntbit(T s) { return s == 0 ? 0 : cntbit(s >> 1) + (s & 1); }

const int bfsz = 1 << 16;
char bf[bfsz + 5];
int rsz = 0;
int ptr = 0;
char gc() {
    if (rsz <= 0) {
        ptr = 0;
        rsz = (int) fread(bf, 1, bfsz, stdin);
        if (rsz <= 0)
            return EOF;
    }
    --rsz;
    return bf[ptr++];
}
void ga(char &c) {
    c = EOF;
    while (!isalpha(c))
        c = gc();
}
int gs(char s[]) {
    int l = 0;
    char c = gc();
    while (isspace(c))
        c = gc();
    while (c != EOF && !isspace(c)) {
        s[l++] = c;
        c = gc();
    }
    s[l] = '\0';
    return l;
}
template<class T> bool gi(T &v) {
    v = 0;
    char c = gc();
    while (c != EOF && c != '-' && !isdigit(c))
        c = gc();
    if (c == EOF)
        return false;
    bool neg = c == '-';
    if (neg)
        c = gc();
    while (isdigit(c)) {
        v = v * 10 + c - '0';
        c = gc();
    }
    if (neg)
        v = -v;
    return true;
}

typedef pair<int, int> II;

const ld PI = acos(-1.0);
const ld eps = 1e-13;

const int dr[] = {0, +1, 0, -1};
const int dc[] = {+1, 0, -1, 0};

const int inf = (int)1e9 + 5;
const ll linf = (ll)1e16 + 5;
const ll mod = (ll)1e9 + 7;
#define maxn 100005
#define maxe 20005

int n;
ll x[maxn], v[maxn];

ld cal(ld t){
    ld MIN = inf * 1.0 * inf * 10;
    ld MAX = -MIN;
    For(i, 1, n){
        MIN = min(MIN, x[i] + v[i] * t);
        MAX = max(MAX, x[i] + v[i] * t);
    }
    return (MAX - MIN) / 2;
}

//ld tinh(){
//  ld res = cal(0);
//  For(i, 1, n) For(j, i + 1, n) if(v[i] != v[j] && (x[i] - x[j]) * (v[i] - v[j]) < 0){
//      ld t = (x[i] - x[j]) * 1.0 / (v[j] - v[i]);
//      res = min(res, cal(t));
//  }
//  return res;
//}

void solve(){

    cout << fixed << setprecision(3);
    For(i, 1, n) scanf("%lld", &x[i]);
    For(i, 1, n) scanf("%lld", &v[i]);

    ld u = 0, v = inf * 10.0, r1, r2;
    Rep(run, 300){
        r1 = (u + u + v) / 3;
        r2 = (u + v + v) / 3;
        if(cal(r1) < cal(r2)){
            v = r2;
        }
        else u = r1;
    }

//  ld res = tinh();
//  if(abs(cal(u) - res) > 0.000001){
//      cout << "WA" << " " << cal(u) << " " << res << endl;
//  }
    cout << cal(u) << endl;

}

void gen(){
    freopen("in.txt", "w", stdout);
    Rep(run, 100){
        n = 100;
        cout << n << endl;
        For(i, 1, n) cout << rand() << " "; puts("");
        For(i, 1, n) cout << rand() << " "; puts("");
    }
}

int main(){
    srand(time(NULL));
//  gen();
//  freopen("in.txt", "r", stdin);
//  freopen("out.txt", "w", stdout);
//  cout << 1 << endl;
    while(cin >> n){
        solve();
    }
    return 0;
}