LeetCode 135 Candy

class Solution {
public:
    int can[100005];
    int a[100005];
    vector<int> b[100005];
    int tag[100005];
    int candy(vector<int>& ratings) {
        
        int l=ratings.size();
        int ans=0;
        memset(vis,0,sizeof(vis));
        for(int i=0;i<l;i++)
        {
            a[i]=ratings[i];
        }
        sort(a,a+l);
        int rank=0;
        for(int i=0;i<l;i++)
        {
            if(tag[a[i]]==0)
                tag[a[i]]=++rank;
        }
        for(int i=0;i<l;i++)
        {
            b[tag[ratings[i]]].push_back(i);
        }
        for(int i=1;i<=rank;i++)
        {
            for(int k=0;k<b[i].size();k++)
            {
                int j=b[i][k];
                 int x=1,y=1;
                 if(j-1>=0&&can[j-1]!=0)
                 {
                      if(ratings[j-1]==ratings[j])
                          x = 1;
                      else
                          x=can[j-1]+1;
                            
                 }
                 if(j+1<l&&can[j+1]!=0)
                 {
                      if(ratings[j+1]==ratings[j])
                           y=1;
                      else
                           y=can[j+1]+1;
                 }
                        
                 can[j]=max(x,y); 
                 ans+=can[j];
             }

        }
        
        return ans;
    }
};