DP分类

CodeForces - 699C - Vacations 动态规划

（找最小值dp）

#include<bits/stdc++.h>
using namespace std;

int dp[1000][3];
int a[1000];

int main(){
int n ;
//求最小值，则赋值为inf
memset(dp,100,sizeof(dp));
cin >> n;
for(int i = 1 ; i <= n ;  i++)
    cin >> a[i];
    dp[0][0] = 0;
for(int i = 1;  i <= n ; i++)
{
    dp[i][0] = min(min(dp[i-1][1],dp[i-1][2]),dp[i-1][0]) + 1;
    if(a[i] == 2 || a[i] == 3)
        dp[i][1] = min(dp[i-1][0],dp[i-1][2]);
    if(a[i] == 1 || a[i] == 3)
        dp[i][2] = min(dp[i-1][1] ,dp[i-1][0]);

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