# 1346. Intervals of Monotonicity（ｄｐ）

１３４６

 1 #include <iostream>
2 #include<cstdio>
3 #include<cstring>
4 #include<algorithm>
5 #include<stdlib.h>
6 #include<vector>
7 using namespace std;
8 #define N 200010
9 int p[N],dp[N][2];
10 int main()
11 {
12     int i,a,b;
13     scanf("%d%d",&a,&b);
14     for(i = 1 ; i <= b-a+1 ; i++)
15     scanf("%d",&p[i]);
16     dp[1][0] = 1;
17     dp[1][1] = 1;
18     for(i = 2; i <= b-a+1 ; i++)
19     {
20         if(p[i]>p[i-1])
21         {
22             dp[i][0] = min(dp[i-1][1]+1,dp[i-1][0]);
23             dp[i][1] = min(dp[i-1][0]+1,dp[i-1][1]+1);
24         }
25         else if(p[i]<p[i-1])
26         {
27             dp[i][0] = min(dp[i-1][1]+1,dp[i-1][0]+1);
28             dp[i][1] = min(dp[i-1][0]+1,dp[i-1][1]);
29         }
30         else
31         {
32             dp[i][0] = min(dp[i-1][0],dp[i-1][1]+1);
33             dp[i][1] = min(dp[i-1][1],dp[i-1][0]+1);
34         }
35     }
36     int ans = min(dp[b-a+1][0],dp[b-a+1][1]);
37     printf("%d\n",ans);
38     return 0;
39 }
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posted @ 2013-10-20 19:33  _雨  阅读(262)  评论(0编辑  收藏  举报