6485: Boxes and Candies（贪心）

6485: Boxes and Candies

时间限制: 1 Sec   内存限制: 128 MB
提交: 315   解决: 114
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题目描述

There are N boxes arranged in a row. Initially, the i-th box from the left contains ai candies.
Snuke can perform the following operation any number of times:
Choose a box containing at least one candy, and eat one of the candies in the chosen box.
His objective is as follows:
Any two neighboring boxes contain at most x candies in total.
Find the minimum number of operations required to achieve the objective.

Constraints
2≤N≤105
0≤ai≤109
0≤x≤109

输入

The input is given from Standard Input in the following format:
N x
a1 a2 … aN

输出

Print the minimum number of operations required to achieve the objective.

样例输入

3 3
2 2 2

样例输出

1

提示

Eat one candy in the second box. Then, the number of candies in each box becomes (2,1,2).

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<stdlib.h>
#include<algorithm>
using namespace std;
int main()
{
    long long n, x, a[100005];
    scanf("%lld%lld", &n, &x);
    for(int i=0;i<n;i++)
        scanf("%lld", &a[i]);
    long long ans=0, temp=0;
    for(int i=0;i<n;i++)
    {
        if(temp+a[i]<=x)
            temp=a[i];
        else
        {
            ans+=a[i]+temp-x;
            temp=a[i]-(a[i]+temp-x);
        }
    }
    printf("%lld\n", ans);
    return 0;
} 
/**************************************************************
    Problem: 6485
    User: ldu_reserver201701
    Language: C++
    Result: 正确
    Time:28 ms
    Memory:1752 kb
****************************************************************/