1. 首页
2. DP
3. 本页

Codeforces 698A Vacations (DP)

简单dp~~

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define mp make_pair
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;
const double eps=1e-5;
const double pi=acos(-1.0);
const int mod=1e9+7;
const int INF=0x3f3f3f3f;
const int MAXN=100000+10;
const int MAXM=1000000+10;

int a[1010];
int dp[1010][3];

int main()
{
    int n;
    scanf("%d",&n);
    for(int i=1; i<=n; ++i)
    {
        scanf("%d",a+i);
    }
    for(int i=1; i<=n; ++i)
    {
        dp[i][0]=min(dp[i-1][0],min(dp[i-1][1],dp[i-1][2]))+1;
        if(a[i]==1 || a[i]==3)
        {
            dp[i][1]=min(dp[i-1][0],dp[i-1][2]);
        }
        else
        {
            dp[i][1]=INF;
        }
        if(a[i]==2 || a[i]==3)
        {
            dp[i][2]=min(dp[i-1][0],dp[i-1][1]);
        }
        else
        {
            dp[i][2]=INF;
        }
    }

    cout<<min(dp[n][0],min(dp[n][1],dp[n][2]))<<endl;

    return 0;
}