#include <bits/stdc++.h>
#define pb push_back
using namespace std;
//#include "shortcut.h"
long long inf = 1e16;
long long find_shortcut(int n, vector<int> l, vector<int> d, int c){
vector<long long> pre(n);
for(int i = 0; i < n-1; i++){
pre[i+1] = pre[i] + l[i];
}
vector<long long> lfar(n), rfar(n);
lfar[0] = d[0];
for(int i = 1; i < n; i++){
if(d[i] > lfar[i-1] + l[i-1]) lfar[i] = d[i];
else lfar[i] = lfar[i-1] + l[i-1];
}
rfar[n-1] = d[n-1];
for(int i = n-2; i >= 0; i--){
if(d[i] > rfar[i+1] + l[i]) rfar[i] = d[i];
else rfar[i] = rfar[i+1] + l[i];
}
vector<long long> precalcl(n), precalcr(n);
for(int i = 1; i < n; i++){
precalcl[i] = max(precalcl[i-1], (long long)(lfar[i-1] + l[i-1] + d[i]));
}
for(int i = n-2; i >= 0; i--){
precalcr[i] = max(precalcr[i+1], (long long)(rfar[i+1] + l[i] + d[i]));
}
long long ans;
long long val = 0;
for(int i = 0; i < n-1; i++){
val = max(val, lfar[i] + rfar[i+1] + l[i]);
}
ans = val;
for(int l = 0; l < n-1; l++){
long long maxla = precalcl[l];
long long L = maxla, R = ans;
while(L < R){
long long M = (L + R)/2;
int limr2 = n-1;
for(int j = l+1; j < n; j++){
long long clen = (pre[j] - pre[l] + c);
long long val = lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l]));
if(val > M) limr2 = j-1;
} // L-M
if(limr2 < l+1){
L = M+1;
continue;
}
int l2 = l+1, r2 = limr2;
while(l2 < r2){
int r = (l2 + r2)/2;
long long dis1 = 0;
dis1 = lfar[l] + rfar[r] + c; // L-R
dis1 = max(dis1, precalcr[r]); // R-R
long long clen = pre[r] - pre[l] + c;
for(int j = l; j < r; j++){
dis1 = max(dis1, rfar[r] + (long long)d[j] + min(pre[r] - pre[j], clen - (pre[r] - pre[j])));
} // R-M
//cout<<r<<" icin dis1 = "<<dis1<<endl;
if(dis1 <= M) r2 = r;
else l2 = r + 1;
}
int shouldbiggerthan = l2;
l2 = l+1, r2 = limr2;
while(l2 < r2){
int r = (l2 + r2 + 1)/2;
long long dis2 = 0;
long long clen = pre[r] - pre[l] + c;
for(int j = l+1; j <= r; j++){
dis2 = max(dis2, lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l])));
} // L-M
for(int j = l+1; j < r; j++){ // M-M
long long addj = d[j];
for(int j2 = j+1; j2 < r; j2++){
long long addj2 = d[j2];
dis2 = max(dis2, min(pre[j2] - pre[j], clen - (pre[j2] - pre[j])) + addj + addj2);
}
}
//cout<<r<<" icin dis2 = "<<dis2<<endl;
if(dis2 <= M) l2 = r;
else r2 = r - 1;
}
int shouldsmallerthan = l2;
//cout<<l<<" deyiz. -> "<<M<<" icin denedik => "<<shouldbiggerthan<<" "<<shouldsmallerthan<<endl;
if(shouldbiggerthan <= shouldsmallerthan){
bool check = 1;
int r = shouldsmallerthan;
long long dis1 = lfar[l] + rfar[r] + c; // L-R
dis1 = max(dis1, precalcr[r]); // R-R
long long dis2 = 0;
long long clen = pre[r] - pre[l] + c;
for(int j = l+1; j <= r; j++){
dis2 = max(dis2, lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l])));
} // L-M
for(int j = l; j < r; j++){
dis2 = max(dis2, rfar[r] + (long long)d[j] + min(pre[r] - pre[j], clen - (pre[r] - pre[j])));
} // R-M
for(int j = l+1; j < r; j++){ // M-M
long long addj = d[j];
for(int j2 = j+1; j2 < r; j2++){
long long addj2 = d[j2];
dis2 = max(dis2, min(pre[j2] - pre[j], clen - (pre[j2] - pre[j])) + addj + addj2);
}
}
//cout<<l<<" deyiz. -> "<<M<<" icin denedik => "<<shouldbiggerthan<<" "<<shouldsmallerthan<<" veeeee dis1 === "<<dis1<<" ve kafa bırakmayan dis22222 === "<<dis2<<endl;
if(max(dis1, dis2) > M) check = 0;
if(check) R = M;
else L = M + 1;
}
else L = M + 1;
}
ans = min(ans, L);
}
return ans;
}
int main(){
int n, c;
assert(2 == scanf("%d%d", &n, &c));
std::vector<int> l(n - 1);
std::vector<int> d(n);
for (int i = 0; i < n - 1; i++)
assert(1 == scanf("%d", &l[i]));
for (int i = 0; i < n; i++)
assert(1 == scanf("%d", &d[i]));
long long t = find_shortcut(n, l, d, c);
printf("%lld\n", t);
return 0;
}
Compilation message
/usr/bin/ld: /tmp/ccUVtxSV.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/cchrxvgY.o:shortcut.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
