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?
Have you met this question in a real interview?
Yes
Example
Given ratings = [1, 2], return 3.
Given ratings = [1, 1, 1], return 3.
Given ratings = [1, 2, 2], return 4. ([1,2,1]).
LeetCode上的原题，请参见我之前的博客Candy。
class Solution {
public:
/**
* @param ratings Children's ratings
* @return the minimum candies you must give
*/
int candy(vector<int>& ratings) {
if (ratings.empty()) return ;
int res = , n = ratings.size();
vector<int> dp(n, ), dp2 = dp;
for (int i = ; i < n; ++i) {
if (ratings[i] > ratings[i - ]) dp[i] = dp[i - ] + ;
else dp[i] = ;
}
for (int i = n - ; i >= ; --i) {
if (ratings[i] > ratings[i + ]) dp2[i] = dp2[i + ] + ;
else dp2[i] = ;
}
for (int i = ; i < n; ++i) {
res += max(dp[i], dp2[i]);
}
return res;
}
};