力扣第84场双周赛复盘

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class Solution {
    public List<List<Integer>> mergeSimilarItems(int[][] items1, int[][] items2) {
        TreeMap<Integer, Integer> map = new TreeMap<>();
        for (int[] a : items1)
            map.put(a[0], map.getOrDefault(a[0], 0) + a[1]);
        for (int[] a : items2)
            map.put(a[0], map.getOrDefault(a[0], 0) + a[1]);
        List<List<Integer>> ans = new ArrayList<>();
        for (int key : map.keySet())
            ans.add(List.of(key, map.get(key)));
        return ans;
    }
}

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class Solution {
    public long countBadPairs(int[] nums) {
        int n = nums.length;
        long ans = (long) n * (n - 1) / 2;
        Map<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < n; i++) {
            int x = i - nums[i];
            ans -= map.getOrDefault(x, 0);
            map.put(x, map.getOrDefault(x, 0) + 1);
        }
        return ans;
    }
}

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class Solution {
    public long taskSchedulerII(int[] tasks, int space) {
        HashMap<Integer, Long> map = new HashMap<>(); // 任务起始时间
        long ans = 0;
        for (int task : tasks) {
            // 当前任务开始之前必须上个任务结束并且上个同类型任务间隔 space 天
            ans = Math.max(ans + 1, map.getOrDefault(task, 0L));
            map.put(task, ans + space + 1);
        }
        return ans;
    }
}

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class Solution {
    public long minimumReplacement(int[] nums) {
        long ans = 0;
        int next = Integer.MAX_VALUE;
        for (int i = nums.length - 1; i >= 0; i--) {
            if (nums[i] > next) {
                int x = (nums[i] + next - 1) / next; // 向上取整
                ans += x - 1;
                next = nums[i] / x;
            } else {
                next = nums[i];
            }
        }
        return ans;
    }
}