// name = shortcut_c.c, type = c.gcc
#include "shortcut_c.h"
#include <stdio.h>
#include <stdlib.h>
typedef long long ll;
typedef struct llpair {
ll fi;
ll se;
} llpair;
#define maxn 1000005
const ll inf = 1e18;
ll x[maxn], d[maxn];
int n, C;
llpair q[maxn];
int ans1, ans2;
llpair mp(ll fi, ll se) {
llpair res;
res.fi = fi;
res.se = se;
return res;
}
ll min(ll a, ll b) {
return a < b ? a : b;
}
ll max(ll a, ll b) {
return a > b ? a : b;
}
ll max3(ll a, ll b, ll c) {
return max(max(a, b), c);
}
int can(ll diam)
{
// cout << "can " << diam << endl;
int needleft = 0;
ll maxsum = inf;
ll minsum = -inf;
ll maxdif = inf;
ll mindif = -inf;
llpair mostleft;
mostleft.fi = inf;
mostleft.se = -inf;
llpair mostright;
mostright.fi = -inf;
mostright.se = -inf;
int l = 0;
int r = 0;
for (int i = 0; i < n; i++)
{
// no need to check whether it is "small" or not, because in case of "small" its square is inside "big"'s square
while (r > l && x[i] - q[l].fi + d[i] > diam)
{
int wh = q[l].se;
l++;
if (x[wh] - d[wh] < mostleft.fi - mostleft.se) mostleft = mp(x[wh], d[wh]);
if (x[wh] + d[wh] > mostright.fi + mostright.se) mostright = mp(x[wh], d[wh]);
needleft = 1;
}
if (needleft)
{
maxsum = min(maxsum, (mostleft.fi + diam - C - d[i] - mostleft.se) + x[i]);
minsum = max(minsum, (mostright.fi - (diam - C - d[i] - mostright.se)) + x[i]);
maxdif = min(maxdif, x[i] - (mostright.fi - (diam - C - d[i] - mostright.se)));
mindif = max(mindif, x[i] - (mostleft.fi + diam - C - d[i] - mostleft.se));
}
while (r > l && q[r - 1].fi > x[i] - d[i]) r--;
q[r++] = mp(x[i] - d[i], i);
}
// cout << minsum << ' ' << maxsum << ' ' << mindif << ' ' << maxdif << endl;
if (maxsum < minsum || maxdif < mindif) return 0;
int curdif = 0;
int cursum = n;
for (int i = 0; i < n; i++)
{
while (curdif < n && x[curdif] - x[i] < mindif) curdif++;
while (cursum > 0 && x[cursum - 1] + x[i] >= minsum) cursum--;
int cur = max3(cursum, curdif, i + 1);
if (cur < n && x[cur] + x[i] <= maxsum && x[cur] - x[i] <= maxdif)
{
ans1 = i;
ans2 = cur;
return 1;
}
}
return 0;
}
long long find_shortcut(int N, int* L0, int* L, int C_)
{
n = N;
C = C_;
ll cursum = 0;
for (int i = 0; i < n; i++)
{
d[i] = L[i];
x[i] = cursum;
if (i + 1 < n) cursum += L0[i];
}
ll l = 0;
ll r = inf;
while (r - l > 1)
{
ll mid = (l + r) / 2;
if (can(mid)) r = mid;
else l = mid;
}
can(r);
return r;
}
