求助玄学WA

#include<bits/stdc++.h>
using namespace std;
const int MAXN=200005;
int n;
int a[MAXN];
int dp[MAXN][2];
int ans=-0x7fffffff;
int main(){
	freopen("b.in","r",stdin);
	freopen("b.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		scanf("%d",&a[i]);
		dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
		dp[i][1]=max(dp[i-1][1]+a[i],a[i]);
		ans=max(ans,max(dp[i][0],dp[i][1]));
	}
//	cout<<"1217778"<<endl;
//	for(int i=1;i<=n;i++)cout<<dp[i][0]<<" "<<dp[i][1]<<endl;
	printf("%d\n",max(dp[n][0],dp[n][1]));
	return 0;
}