函数最值

贪心，负数为搞成0不选即可。

#include <iostream>#include <cstdio>#include <cstring>#define ll long longusing namespace std;const int maxm=110000;ll a[maxm],sum[maxm];char s[maxm];ll x=0;int main(){    int n;    scanf("%d",&n);    for(int i=1;i<=n;i++)    {        scanf("%lld",a+i);        sum[i]=sum[i-1];        sum[i]+=max(a[i],x);    }    scanf("%s",s+1);    int len=strlen(s+1);    ll c=0,ans=0;    for(int i=len;i>=1;i--)     if(s[i]=='1')     {        ans=max(ans,c+sum[i-1]);        c+=max(a[i],x);      }     printf("%lld ",max(ans,c));}