codeforces+contest978problemE. Bus Video System+思维

最新推荐文章于 2020-05-19 12:47:20 发布

ujn20161222

最新推荐文章于 2020-05-19 12:47:20 发布

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本文链接：https://blog.youkuaiyun.com/ujn20161222/article/details/80308257

本文介绍了一种公交车视频监控系统，该系统记录了乘客数量在各个站点的变化，并通过一系列整数记录来展示乘客数量的变化情况。文章探讨了如何确定初始乘客数量的可能性，考虑到了车辆的容量限制。

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The busses in Berland are equipped with a video surveillance system. The system records information about changes in the number of passengers in a bus after stops.

If $x$

is the number of passengers in a bus just before the current bus stop and

y

is the number of passengers in the bus just after current bus stop, the system records the number

y - x

. So the system records show how number of passengers changed.

The test run was made for single bus and $n$

bus stops. Thus, the system recorded the sequence of integers

a_{1}, a_{2}, \dots, a_{n}

(exactly one number for each bus stop), where

a_{i}

is the record for the bus stop

i

. The bus stops are numbered from

1

n

in chronological order.

Determine the number of possible ways how many people could be in the bus before the first bus stop, if the bus has a capacity equals to $w$

(that is, at any time in the bus there should be from

0

w

passengers inclusive).

Input

The first line contains two integers $n$

and

w

(1 \leq n \leq 1000, 1 \leq w \leq 10^{9})

— the number of bus stops and the capacity of the bus.

The second line contains a sequence $a_{1}, a_{2}, \dots, a_{n}$

(- 10^{6} \leq a_{i} \leq 10^{6})

, where

a_{i}

equals to the number, which has been recorded by the video system after the

i

-th bus stop.

Output

Print the number of possible ways how many people could be in the bus before the first bus stop, if the bus has a capacity equals to $w$

. If the situation is contradictory (i.e. for any initial number of passengers there will be a contradiction), print 0.

Examples

Input

Copy

3 5
2 1 -3

Output

Copy

Input

Copy

2 4
-1 1

Output

Copy

Input

Copy

4 10
2 4 1 2

Output

Copy

Note

In the first example initially in the bus could be $0$

1

2

passengers.

In the second example initially in the bus could be $1$

2

3

4

passengers.

In the third example initially in the bus could be $0$

1

passenger.

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i,a,b) for(int i=a;i<=b;i++)
ll rd(){
    ll x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}

int main(){
  // freopen("in.txt","r",stdin);
   int n=rd(),w=rd();
   ll sum=0;
   ll lf=0,rg=w;
   while(n--){
        ll a=rd();
        sum+=a;
        lf=max(lf,-sum);
        rg=min(rg,w-sum);
        //cout<<lf<<" "<<rg<<endl;
   }

   if(lf<=rg)
    return printf("%d\n",rg-lf+1);
   return puts("0"),0;
}