codeforces 201C Fragile Bridges

wa代码

#include<iostream>
#include<math.h>
#include<stdio.h>
#include<algorithm>
#include<string.h>
#include<vector>
#include<map>
using namespace std;
typedef long long lld;
const int oo=0x3f3f3f3f;
const lld OO=1LL<<61;
const int MOD=1000000007;
#define eps 1e-6
#define maxn 100005
lld l[maxn][2],r[maxn][2];///往左不回来，往左回来，往右不回来，往右回来。
int b[maxn];int main()
{int n;while(scanf("%d",&n)!=EOF){for(int i=2;i<=n;i++)scanf("%d",&b[i]);memset(l,0,sizeof l);memset(r,0,sizeof r);for(int i=2;i<=n;i++){if(b[i]%2==0)l[i][0]++;else break;}for(int i=n-1;i>=1;i--){if(b[i+1]%2==0)r[i][0]++;else break;}for(int i=2;i<=n;i++){if(b[i]%2==1)l[i][0]+=l[i-1][0]+b[i];elsel[i][0]+=l[i-1][0]+b[i]-1;if(b[i]==1)l[i][1]=0;else if(b[i]%2==0)l[i][1]+=l[i-1][1]+b[i];elsel[i][1]+=l[i-1][1]+b[i]-1;}for(int i=n-1;i>=1;i--){if(b[i+1]%2==1)r[i][0]+=r[i+1][0]+b[i+1];elser[i][0]+=r[i+1][0]+b[i+1]-1;if(b[i+1]==1)r[i][1]=0;else if(b[i+1]%2==0)r[i][1]+=r[i+1][1]+b[i+1];elser[i][1]+=r[i+1][1]+b[i+1]-1;}lld ans=0;for(int i=1;i<=n;i++){ans=max(max(ans,l[i][1]+r[i][1]),max(l[i][1]+r[i][0],l[i][0]+r[i][1]));}printf("%I64d\n",ans);}return 0;
}
/**
10
2 2 1 1 1 1 2 2 1
10
1 1 2 2 2 1 1 2 2
//靠！
15
1 2 2 2 2 1 2 2 2 2 2 2 1 1*/

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