135. Candy

Greedy

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class Solution {
    public int candy(int[] ratings) {
        int totalCount = 0;

        int[] counts = new int[ratings.length];
        Arrays.fill(counts, 1);
        totalCount += counts.length;

        for (int i = 1; i < ratings.length; i++) {
            if (ratings[i] > ratings[i - 1]) {
                while (counts[i] <= counts[i - 1]) {
                    counts[i]++;
                    totalCount++;
                }
            }
        }

        for (int i = ratings.length - 2; i >= 0; i--) {
            if (ratings[i] > ratings[i + 1]) {
                while (counts[i] <= counts[i + 1]) {
                    counts[i]++;
                    totalCount++;
                }
            }
        }

        return totalCount;
    }
}

Greedy

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class Solution {
    public int candy(int[] ratings) {
        int[] left = new int[ratings.length];
        Arrays.fill(left, 1);

        for (int i = 1; i < ratings.length; i++) {
            if (ratings[i] > ratings[i - 1]) {
                left[i] = left[i - 1] + 1;
            }
        }

        int count = left[left.length - 1];

        int[] right = new int[ratings.length];
        Arrays.fill(right, 1);

        for (int i = ratings.length - 2; i >= 0; i--) {
            if (ratings[i] > ratings[i + 1]) {
                right[i] = right[i + 1] + 1;
            }

            count += Math.max(left[i], right[i]); // 注意该逻辑在 if 块外执行
        }

        return count;
    }
}

References

135. Candy