leetcode 502. IPO

multiset 与 priority_queue 

联系: 可以实现 大小顶堆;

区别: 删除元素时,multiset 会把相同元素值都删除!!

代码 1 :(Accept) 

class Solution {
public:
    int findMaximizedCapital(int k, int W, vector<int>& Profits, vector<int>& Capitals) {
        multimap<int,int> mp;
        for (int i = 0; i < Capitals.size(); ++i)
            mp.insert (make_pair(Capitals[i], Profits[i]));
        priority_queue<int> heap;
        while (k--){
            for (auto iter = mp.begin(); iter != mp.end();){
                if (iter->first <= W){
                    heap.push(iter->second); 
                    iter = mp.erase (iter);
                }
                else 
                    break;
            }
            if (!heap.empty()){
                W += heap.top();
                heap.pop();
            }
            else 
                break;
        }
        return W;
    }
};

代码 2 : (Wrong Answer)

class Solution {
public:
    int findMaximizedCapital(int k, int W, vector<int>& Profits, vector<int>& Capitals) {
        multimap<int,int> mp;
        for (int i = 0; i < Capitals.size(); ++i)
            mp.insert (make_pair(Capitals[i], Profits[i]));
        multiset<int> st;
        while (k--){
            for (auto iter = mp.begin(); iter != mp.end();){
                if (iter->first <= W){
                    st.insert (iter->second); 
                    iter = mp.erase (iter);
                }
                else 
                    break;
            }
            if (!st.empty()){
                W += *st.rbegin();
                st.erase (*st.rbegin()); //   st.erase (--st.end()); 这样写就对了
            }
            else 
                break;
        }
        return W;
    }
};

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