URAL 1346. Intervals of Monotonicity(DP)

题目链接

错误的贪了一下，然后D了两下就过了。注意是不上升和不下降。。不是上升和下降。。

 #include <cstring>
 #include <cstdio>
 #include <string>
 #include <iostream>
 #include <algorithm>
 #include <cmath>
 #include <map>
 using namespace std;
 #define INF 100000000
 int p[];
 int dp[];
 int o1[];
 int o2[];
 int main()
 {
     int a,b,i,n;
     scanf("%d%d",&a,&b);
     n = b - a + ;
     for(i = ;i <= n;i ++)
     scanf("%d",&p[i]);
     o1[] = o2[] = ;
     for(i = ;i <= n;i ++)
     {
         if(p[i] >= p[i-])
         o1[i] = o1[i-];
         else
         o1[i] = i;
         if(p[i] <= p[i-])
         o2[i] = o2[i-];
         else
         o2[i] = i;
     }
     for(i = ;i <= n;i ++)
     {
         dp[i] = min(dp[o1[i]-],dp[o2[i]-]) + ;
     }
     printf("%d\n",dp[n]);
     return ;
 }