Leetcode Problem : Candy

Candy

There are N children standing in a line. Each child is assigned a rating value.
You are giving candies to these children subjected to the following requirements:
Each child must have at least one candy.Children with a higher rating get more candies than their neighbors.What is the minimum candies you must give?

Code :

int candy(vector<int> &A) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
    int n = A.size();
    if(n < 2)
     return n;
    bool allDone = false;
    int candies = 0;
    vector<int> c(n,0);
    while(!allDone){
        allDone = true;
        int i = 0;
        while(i < n){
            if(c[i] == 0){ 
                int left,right;
                if(i == n - 1)
                    right = INT_MAX;
                else
                    right = A[i + 1];
                if(i == 0)
                    left = INT_MAX;
                else
                    left = A[i - 1];
                if(A[i] <= left && A[i] <= right){
                    int num = 1;
                    c[i] = num;candies += num;allDone = false;
                }
                else if(A[i] <= left && A[i] > right){
                    if(c[i + 1] != 0){
                        int num = c[i + 1] + 1;
                        c[i] = num;candies += num;allDone = false;
                    }
                }
                else if(A[i] > left && A[i] <= right){
                    if(c[i - 1] != 0){
                        int num = c[i - 1] + 1;
                        c[i] = num;candies += num;allDone = false;
                    }
                }
                else{
                    if(c[i + 1] != 0 && c[i - 1] != 0){
                        int num = max(c[i + 1],c[i - 1]) + 1;
                        c[i] = num;candies += num;allDone = false;
                    }
                }
            }
            i = i + 1;
        }
    }
    return candies;
}