506.相对名次.md

方法一：大顶堆

这道题看到题目就会想到排序，但是问题是排序之后元素之间的顺序可能会被改变，最后的输出结果要和原始数组中元素的位置是对应的，那就需要将元素的值和下标一起保存起来，再根据元素值进行排序。

class Solution {
    public String[] findRelativeRanks(int[] score) {
        String[] res = new String[score.length];
        // 大顶堆
        PriorityQueue<int[]> pq = new PriorityQueue<>(new Comparator<int[]>() {
            public int compare(int[] nums1, int[] nums2) {
                return nums1[0] != nums2[0] ? nums2[0] - nums1[0] : nums1[0] - nums2[0];
            }
        });
        for (int i = 0; i < score.length; i++) {
            pq.offer(new int[]{score[i], i});
        }
        int i = 1;
        while (!pq.isEmpty()) {
            if (i == 1) {
                res[pq.peek()[1]] = "Gold Medal";
            } else if (i == 2) {
                res[pq.peek()[1]] = "Silver Medal";
            } else if (i == 3) {
                res[pq.peek()[1]] = "Bronze Medal";
            } else {
                res[pq.peek()[1]] = i + "";
            }
            pq.poll();
            i++;
        }
        return res;
    }
}

方法二：使用Arrays.sort()来排序

class Solution {
    public String[] findRelativeRanks(int[] score) {
        String[] res = new String[score.length];
        String[] medals = new String[]{"Gold Medal", "Silver Medal", "Bronze Medal"};
        int[][] arr = new int[score.length][2];
        for (int i = 0; i < score.length; i++) {
            arr[i][0] = score[i];
            arr[i][1] = i;
        }
        Arrays.sort(arr, (a, b) -> b[0] - a[0]);
        for (int i = 0; i < score.length; i++) {
            if (i >= 3) {
                res[arr[i][1]] = Integer.toString(i + 1);
            } else {
                res[arr[i][1]] = medals[i];
            }
        }
        return res;
    }
}