[LeetCode]506. Relative Ranks(相对应排名)

506. Relative Ranks

Given scores of N athletes, find their relative ranks and the people with the top three highest scores, who will be awarded medals: “Gold Medal”, “Silver Medal” and “Bronze Medal”.

Example 1:

Input: [5, 4, 3, 2, 1]
Output: ["Gold Medal", "Silver Medal", "Bronze Medal", "4", "5"]
Explanation: 
    The first three athletes got the top three highest scores, so they got "Gold Medal", "Silver Medal" and "Bronze Medal". 
    For the left two athletes, you just need to output their relative ranks according to their scores.

Note:

1. N is a positive integer and won’t exceed 10,000.
2. All the scores of athletes are guaranteed to be unique.

题目大意：
给一个数组，记录N个运动员的分数，返回他们的排名数组，前三名应该为”Gold Medal”, “Silver Medal”, “Bronze Medal”，其余是数字名次
N<<10000,运动员分数均是不同的

思路：
复制一个相同数组arr ，排序，定义一个排名数组，从原数组中寻找与arr[j]相同元素,在排名数组中对应位置赋值为j+1（记录运动员排名）, j=0,1,2时特殊处理为”Gold Medal”, “Silver Medal”, “Bronze Medal”

C++

class Solution {
public:
    vector<string> findRelativeRanks(vector<int>& nums) {
        vector<int> arr = nums;//复制一个相同的数组
        auto cmp = [](int a, int b) {return a > b;};
        sort(arr.begin(), arr.end(), cmp);//将arr排序
        vector<string> result(nums.size());
        //从nums中寻找与arr[j]相同元素,在result中对应位置赋值为j+1, j=0,1,2时特殊处理
        for (int i = 0; i < nums.size(); i++) {
            for (int j = 0; j < nums.size(); j++) {
                if (nums[i] == arr[j]) {
                    switch(j) {
                        case 0:
                            result[i] = "Gold Medal";
                            break;
                        case 1:
                            result[i] = "Silver Medal";
                            break;
                        case 2:
                            result[i] = "Bronze Medal";
                            break;
                        default:
                            result[i] = to_string(j + 1);
                            break;
                    }
                    break;
                }
            }
        }
        return result;
    }
};

注意：

• auto 总是编译错误，查了查好像是编译器问题，在LeetCode上运行能AC
• 查找可以换成二分查找提高效率传送门
• Arrays.binarySearch(arr[], int a, Collections.reverseOrder());