ural 1346. Intervals of Monotonicity

  1 /**
  2 Create By yzx - stupidboy
  3 */
  4 #include <cstdio>
  5 #include <cstring>
  6 #include <cstdlib>
  7 #include <cmath>
  8 #include <deque>
  9 #include <vector>
 10 #include <queue>
 11 #include <iostream>
 12 #include <algorithm>
 13 #include <map>
 14 #include <set>
 15 #include <ctime>
 16 #include <iomanip>
 17 using namespace std;
 18 typedef long long LL;
 19 typedef double DB;
 20 #define For(i, s, t) for(int i = (s); i <= (t); i++)
 21 #define Ford(i, s, t) for(int i = (s); i >= (t); i--)
 22 #define Rep(i, t) for(int i = (0); i < (t); i++)
 23 #define Repn(i, t) for(int i = ((t)-1); i >= (0); i--)
 24 #define rep(i, x, t) for(int i = (x); i < (t); i++)
 25 #define MIT (2147483647)
 26 #define INF (1000000001)
 27 #define MLL (1000000000000000001LL)
 28 #define sz(x) ((int) (x).size())
 29 #define clr(x, y) memset(x, y, sizeof(x))
 30 #define puf push_front
 31 #define pub push_back
 32 #define pof pop_front
 33 #define pob pop_back
 34 #define ft first
 35 #define sd second
 36 #define mk make_pair
 37 inline void SetIO(string Name)
 38 {
 39     string Input = Name+".in",
 40     Output = Name+".out";
 41     freopen(Input.c_str(), "r", stdin),
 42     freopen(Output.c_str(), "w", stdout);
 43 }
 44 
 45 
 46 inline int Getint()
 47 {
 48     int Ret = 0;
 49     char Ch = ‘ ‘;
 50     bool Flag = 0;
 51     while(!(Ch >= ‘0‘ && Ch <= ‘9‘))
 52     {
 53         if(Ch == ‘-‘) Flag ^= 1;
 54         Ch = getchar();
 55     }
 56     while(Ch >= ‘0‘ && Ch <= ‘9‘)
 57     {
 58         Ret = Ret * 10 + Ch - ‘0‘;
 59         Ch = getchar();
 60     }
 61     return Flag ? -Ret : Ret;
 62 }
 63 
 64 const int N = 100010;
 65 int a, b, Arr[N];
 66 int Up[N], Down[N];
 67 
 68 inline void Input()
 69 {
 70     scanf("%d%d", &a, &b);
 71     For(i, a, b) scanf("%d", Arr + i);
 72 }
 73 
 74 inline void Solve()
 75 {
 76     Up[a] = Down[a] = 1;
 77     For(i, a + 1, b)
 78     {
 79         if(Arr[i] > Arr[i - 1])
 80         {
 81             Up[i] = min(Up[i - 1], Down[i - 1] + 1);
 82             Down[i] = min(Up[i - 1] + 1, Down[i - 1] + 1);
 83         }
 84         else if(Arr[i] < Arr[i - 1])
 85         {
 86             Down[i] = min(Down[i - 1], Up[i - 1] + 1);
 87             Up[i] = min(Up[i - 1] + 1, Down[i - 1] + 1);
 88         }
 89         else
 90         {
 91             Up[i] = min(Up[i - 1], Down[i - 1] + 1);
 92             Down[i] = min(Down[i - 1], Up[i - 1] + 1);
 93         }
 94     }
 95 
 96     int Ans = min(Up[b], Down[b]);
 97     printf("%d\n", Ans);
 98 }
 99 
100 int main()
101 {
102     #ifndef ONLINE_JUDGE
103     SetIO("I");
104     #endif
105     Input();
106     Solve();
107     return 0;
108 }