leetcode Question: 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?


Scan the rating array from left to right and then from right to left. In every scan just consider the rising order (l->r: r[i]>r[i-1] or r->l: r[i]>r[i+1]), assign +1 candies to the rising position.
The final candy array is the maximum (max(right[i],left[i])) in each position.
The total candies is the sum of the final candy array.

The time complexity is O(n).


class Solution {
    int getC(vector<int> &r){
        vector<int> lc(r.size(),1);
        vector<int> rc(r.size(),1);
        int res=0;
        for (int i=1;i<lc.size();i++){
            if (r[i]>r[i-1]){
        for (int i=rc.size()-2;i>=0;i--){
            if (r[i]>r[i+1]){
        for (int i=0;i<r.size();i++){
        return res;
    int candy(vector<int> &ratings) {
        return getC(ratings);

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