代码

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;
int h[100000];
int n;
int f(int l,int r)
{
    if (l==r) return h[l];
    int mid=(l+r)>>1;
    return f(l,mid)+f(mid+1,r)-min(h[mid],h[mid+1]);
}
int main()
{
    scanf("%d",&n);
    for (int i=1;i<=n;i++) scanf("%d",h+i-1);
    printf("%d\n",f(0,n-1));
    return 0;
}

评测结果