wenbao与cf上升序列（最多改变一个变为连续严格上升序列）

http://codeforces.com/problemset/problem/446/A

 1 #include <iostream>
 2 using namespace std;
 3 #define ll long long
 4 const int maxn = 1e5+10;
 5 int sum1[maxn], a[maxn], sum2[maxn];
 6 int main(){
 7     int n, ma = -1;
 8     cin>>n;
 9     a[n+1] = 1e9+10;
10     for(int i = 1; i <= n; i++){
11         cin>>a[i];
12         sum1[i] = (a[i] > a[i-1] ? sum1[i-1] + 1 : 1);
13         ma = max(ma, sum1[i]);
14     }
15     ma = min(n,ma+1);
16     for(int i = n; i>=1 ; i--){
17         sum2[i] = (a[i] < a[i+1] ? sum2[i+1] + 1 : 1);
18         if(a[i-1] + 1 < a[i+1]) ma = max(ma, sum2[i+1]+sum1[i-1]+1);
19     }
20     cout<<ma<<endl;
21     return 0;
22 }

只有不断学习才能进步！