#include "bits/stdc++.h"
using namespace std;
#define int long long
#define double long double
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
if(p==0) return 1 % MOD;
int r = bm(b, p >> 1);
if(p&1) return (((r*r) % MOD) * b) % MOD;
return (r*r) % MOD;
}
int inv(int b) {
return bm(b, MOD-2);
}
int fastlog(int x) {
return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
static void run_with_stack_size(void (*func)(void), size_t stsize) {
char *stack, *send;
stack = (char *)malloc(stsize);
send = stack + stsize - 16;
send = (char *)((uintptr_t)send / 16 * 16);
asm volatile(
"mov %%rsp, (%0)\n"
"mov %0, %%rsp\n"
:
: "r"(send));
func();
asm volatile("mov (%0), %%rsp\n" : : "r"(send));
free(stack);
}
void solve(int tc) {
int n;
cin >> n;
int a[n+1];
for(int i=1; i<=n; i++) {
cin >> a[i];
}
int ps[n+1];
ps[0] = 0;
for(int i=1; i<=n; i++) ps[i] = ps[i-1] + a[i];
vector<pair<double, pair<int,int>> > vt;
for(int i=1; i<=n; i++) {
for(int j=i; j<=n; j++) {
double bi = (ps[j] - ps[i-1]) * 1.0 / (j - i + 1);
vt.push_back({bi, {i, j}});
}
}
sort(vt.begin(), vt.end());
bool dp[n+1][n+1], init[n+1][n+1];
for(int i=0; i<=n; i++) {
for(int j=0; j<=n; j++) {
init[i][j] = dp[i][j] = 0;
}
}
int j = -1;
double ans = 1e18;
for(int i=0; i<vt.size(); i++) {
j = max(j, i - 1);
double l = vt[i].first;
if(i > 0) {
int l = vt[i-1].second.first;
int r = vt[i-1].second.second;
init[l][r] = 0;
}
bool good = 0;
while(1) {
for(int k=1; k<=n; k++) for(int l=k; l<=n; l++) dp[k][l] = 0;
for(int k=1; k<=n; k++) {
dp[k][k] = init[k][k];
}
for(int len=2; len<=n; len++) {
for(int k=1; k+len-1<=n; k++) {
dp[k][k+len-1] = init[k][k+len-1] && (dp[k+1][k+len-1] || dp[k][k+len-2]);
}
}
if(dp[1][n]) {
good = 1;
break;
}
if(j + 1 < vt.size()) {
j++;
int l = vt[j].second.first;
int r = vt[j].second.second;
init[l][r] = 1;
}
else break;
}
if(good) {
ans = min(ans, vt[j].first - vt[i].first);
}
}
cout << fixed << setprecision(10) << ans << '\n';
}
void uwu() {
ios::sync_with_stdio(0); cin.tie(0);
int t = 1; //cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
int32_t main() {
#ifdef ONLINE_JUDGE
uwu();
#endif
#ifndef ONLINE_JUDGE
run_with_stack_size(uwu, 1024 * 1024 * 1024); // run with a 1 GiB stack
#endif
}
/*
g++ A.cpp -std=c++17 -O2 -o A
./A < input.txt
*/
Compilation message
seesaw.cpp: In function 'void solve(long long int)':
seesaw.cpp:64:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long double, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
64 | for(int i=0; i<vt.size(); i++) {
| ~^~~~~~~~~~
seesaw.cpp:87:16: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long double, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
87 | if(j + 1 < vt.size()) {
| ~~~~~~^~~~~~~~~~~
seesaw.cpp:66:12: warning: unused variable 'l' [-Wunused-variable]
66 | double l = vt[i].first;
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
344 KB |
Output is correct |
3 |
Correct |
1 ms |
500 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
344 KB |
Output is correct |
3 |
Correct |
1 ms |
500 KB |
Output is correct |
4 |
Correct |
74 ms |
860 KB |
Output is correct |
5 |
Correct |
75 ms |
860 KB |
Output is correct |
6 |
Correct |
69 ms |
856 KB |
Output is correct |
7 |
Correct |
70 ms |
860 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
344 KB |
Output is correct |
3 |
Correct |
1 ms |
500 KB |
Output is correct |
4 |
Correct |
74 ms |
860 KB |
Output is correct |
5 |
Correct |
75 ms |
860 KB |
Output is correct |
6 |
Correct |
69 ms |
856 KB |
Output is correct |
7 |
Correct |
70 ms |
860 KB |
Output is correct |
8 |
Execution timed out |
2057 ms |
72060 KB |
Time limit exceeded |
9 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
344 KB |
Output is correct |
3 |
Correct |
1 ms |
500 KB |
Output is correct |
4 |
Correct |
74 ms |
860 KB |
Output is correct |
5 |
Correct |
75 ms |
860 KB |
Output is correct |
6 |
Correct |
69 ms |
856 KB |
Output is correct |
7 |
Correct |
70 ms |
860 KB |
Output is correct |
8 |
Execution timed out |
2057 ms |
72060 KB |
Time limit exceeded |
9 |
Halted |
0 ms |
0 KB |
- |