365天挑战LeetCode1000题——Day 042 数组序号转换 + 相对名次 离散化处理

这篇讲得不错，核心就是利用哈希表来重新排序

class Solution {
public:
    vector arrayRankTransform(vector& arr) {
        vector other = arr;
        unordered_map _map;
        sort(other.begin(), other.end());
        for (int i = 0; i < other.size(); i++) {
           if (!_map.count(other[i])) {
               _map[other[i]] = _map.size() + 1;
            }
       }
       for (int& num : arr) {
           num = _map[num];
        }
        return arr;
    }
};

class Solution {
public:
    vector findRelativeRanks(vector& score) {
        vector ref = score;
        unordered_map _map;
        vector ans;
        sort(ref.begin(), ref.end(), greater());
        for (int i = 0; i < ref.size(); i++) {
           _map[ref[i]] = _map.size() + 1;
        }
        for (int candidate : score) {
            switch(_map[candidate]) {
                case 1:
                ans.push_back("Gold Medal");
                break;
                case 2:
                ans.push_back("Silver Medal");
                break;
                case 3:
                ans.push_back("Bronze Medal");
                break;
                default:
                ans.push_back(to_string(_map[candidate]));
            }
        }
        return ans;
    }
};