// #pragma once
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18 + 100;
const int maxn = 1e6 + 100;
const int maxl = 20;
int n, C;
ll a[maxn];
int b[maxn];
ll p[2][maxl][maxn];
int lg[maxn];
ll get(int l, int r, int c){
if(l > r) return -INF;
int k = lg[r - l + 1];
return max(p[c][k][l], p[c][k][r-(1<<k)+1]);
}
ll ans(int l, int r){
if(l > r) return -INF;
return get(l, r, 0) + get(l, r, 1);
}
bool ok(ll x){
int tl = 0, tr = n + 1;
while(tl < n && ans(1, tl+1) <= x) tl++;
while(tr > 1 && ans(tr-1, n) <= x) tr--;
for(int l = 1; l <= tl; l++){
for(int r = max(l + 1, tr); r <= n; r++){
if(ans(l+1, r-1) > x) continue;
if(get(1, l, 0) + a[l] + get(r, n, 1) - a[r] + C > x) continue;
if(get(tl+1, r-1, 0) + a[r] + C + get(1, l, 0) + a[l] > x) continue;
if(get(l+1, tr-1, 1) - a[l] + C + get(r, n, 1) - a[r] > x) continue;
return 1;
}
}
return 0;
}
long long find_shortcut(int N, std::vector <int> l, std::vector <int> d, int c){
n = N; C = c;
for(int i = 1; i <= n; i++){
b[i] = d[i-1];
if(i == 1) continue;
a[i] = a[i-1] + l[i - 2];
}
for(int i = 1; i <= n; i++){
p[0][0][i] = b[i] - a[i];
p[1][0][i] = b[i] + a[i];
if(i > 1) lg[i] = lg[i >> 1] + 1;
}
for(int c = 0; c < 2; c++){
for(int k = 1; k <= lg[n]; k++){
for(int i = 1; i + (1<<k) - 1 <= n; i++){
p[c][k][i] = max(p[c][k-1][i], p[c][k-1][i+(1<<(k-1))]);
}
}
}
ll res = ans(1, n);
for(ll l = 0, r = res - 1; l <= r;){
ll mid = (l + r) >> 1;
if(!ok(mid)) l = mid + 1;
else r = mid - 1, res = mid;
}
return res;
}
