1824

class Solution {
public:
    int minSideJumps(vector<int>& obstacles) {
        int n = obstacles.size();
        int dp[n+2][4];
        dp[0][1] = dp[0][3] = 1;
        dp[0][2] = 0;
        for(int i=1; i<n; i++){
            int x = obstacles[i];
            for(int j=1; j<=3; j++){
                if(x == j){
                    dp[i][j] = INT_MAX-5;
                    continue;
                }
                dp[i][j] = dp[i-1][j];
                if(j == 1){
                    int a, b, c;
                    a = dp[i][j];
                    b = (obstacles[i-1] == j && obstacles[i] == 2) ? dp[i-1][2]+2 : dp[i-1][2]+1;
                    c = (obstacles[i-1] == j && obstacles[i] == 3) ? dp[i-1][3]+2 : dp[i-1][3]+1;
                    dp[i][j] = min(a, min(b, c));
                }
                else if(j == 2){
                    int a, b, c;
                    b = dp[i][j];
                    a = (obstacles[i-1]==j && obstacles[i]==1) ? dp[i-1][1]+2 : dp[i-1][1]+1;
                    c = (obstacles[i-1]==j && obstacles[i]==3) ? dp[i-1][3]+2 : dp[i-1][3]+1;
                    dp[i][j] = min(a, min(b, c));
                }
                else if(j == 3){
                    int a, b, c;
                    c = dp[i][j];
                    a = (obstacles[i-1]==j && obstacles[i]==1) ? dp[i-1][1]+2 : dp[i-1][1]+1;
                    b = (obstacles[i-1]==j && obstacles[i]==2) ? dp[i-1][2]+2 : dp[i-1][2]+1;
                    dp[i][j] = min(a, min(b, c));
                }
            }
        }
        return  min(dp[n-1][1], min(dp[n-1][2], dp[n-1][3]));
    }
};