| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 660432 | mychecksedad | Uplifting Excursion (BOI22_vault) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
/* Author : Mychecksdead */
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, F = 2147483646, K = 20;
ll m, l, a[N], sum, ans, b[N][2]; // + and - parts
int dp[700];
void solve(){
cin >> m >> l;
for(int i = 0; i < 2*m+1; ++i) cin >> a[i];
sum = ans = 0;
for(int i = 0; i < 2*m+1; ++i) sum += a[i] * (i - m), ans += a[i], b[i][0] = 0, b[i][1] = a[i];
if(sum == l){
cout << ans;
return;
}
ll c;
if(sum > l){
c = 2*m;
while(sum > l && c >= 0){
if(c==m){
c--;
continue;
}
if(sum - a[c] * (c - m) >= l) sum -= a[c] * (c - m), ans -= a[c], b[c][0] = a[c], b[c][1] = 0;
else{
ll num = (sum - l + (c - m) - 1) / (c - m);
ans -= num;
sum -= num * (c - m);
b[c][0] = num;
b[c][1] = a[c] - num;
break;
}
c--;
}
}else{
c = 0;
while(sum < l && c <= 2*m){
if(c==m){
c++;
continue;
}
if(sum - a[c] * (c - m) <= l) sum -= a[c] * (c - m), ans -= a[c], b[c][0] = a[c], b[c][1] = 0;
else{
ll num = (sum - l) / (c - m);
ans -= num;
sum -= num * (c - m);
b[c][0] = num;
b[c][1] = a[c] - num;
break;
}
c++;
}
}
if(sum > l){
cout << "impossible";
return;
}
int M = 1000;
int v = l - sum + M;
for(int i = 0; i <= 2*M; ++i) dp[i] = MOD;
dp[m] = 0;
for(int i = 0; i <= 2*m; ++i){
if(i==m) continue;
for(int j = 0; j <= 2*M; ++j){
for(int k = 0; k <= min(b[i][0], M); ++k){
int val = j + k * (i - m);
if(val >= 0 && val <= 2*m){
dp[val] = min(dp[val], dp[j] - k);
}
}
}
for(int j = 2*m; j >= 0; --j){
for(int k = 0; k <= min(b[i][1], M); ++k){
int val = j - k * (i - m);
if(val >= 0 && val <= 2*m){
dp[val] = min(dp[val], dp[j] + k);
}
}
}
}
if(dp[v] == MOD) cout << "impossible";
else cout << ans - dp[v];
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}