LeetCode Contest 180

第一题

class Solution {
public:
    vector<int> luckyNumbers (vector<vector<int>>& matrix) {
        
        vector<int> ans;
        
        vector<int> n;
        for(int i=0;i<matrix.size();i++)
        {
            int x=INT_MAX;
            for(int j=0;j<matrix[i].size();j++)
            {
                x=min(x,matrix[i][j]);
            }
            n.push_back(x);
        }
        
        vector<int> m;
        for(int i=0;i<matrix[0].size();i++)
        {
            int x =-1;
            for(int j=0;j<matrix.size();j++)
            {
                x=max(x,matrix[j][i]);
            }
            m.push_back(x);
        }
        
        for(int i=0;i<n.size();i++)
        {
            for(int j=0;j<m.size();j++)
            {
                if(n[i]==m[j])
                    ans.push_back(n[i]);
            }
        }
        
        return ans;
        
    }
};

第二题

class CustomStack {
public:
    int s[1005];
    int m;
    int top;
    CustomStack(int maxSize) {
        m=maxSize;
        top=0;
    }
    
    void push(int x) {
        if(top<m)
         s[top++]=x;
    }
    
    int pop() {
        
        if(top==0)
            return -1;
        int x=s[top-1];
        top--;
        return x;
        
    }
    
    void increment(int k, int val) {
        
        for(int i=0;i<k&&i<top;i++)
        {
            s[i]+=val;
        }
    }
};

/**
 * Your CustomStack object will be instantiated and called as such:
 * CustomStack* obj = new CustomStack(maxSize);
 * obj->push(x);
 * int param_2 = obj->pop();
 * obj->increment(k,val);
 */

第三题

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> nums;
    TreeNode* balanceBST(TreeNode* root) {
        
        fun(root);
        TreeNode* node;
        build(node,0,nums.size()-1);
        return node;
    }
    
    void build(TreeNode* &root,int l,int r)
    {
        int mid = (l+r)/2;
        int x = nums[mid];
        root = new TreeNode(x);
        if(l<=mid-1)
            build(root->left,l,mid-1);
        if(mid+1<=r)
            build(root->right,mid+1,r);
    }
    
    void fun(TreeNode* root)
    {
        if(root!=NULL)
        {
            fun(root->left);
            nums.push_back(root->val);
            fun(root->right);
        }
    }
    
};

第四题

typedef long long int _int;

struct Node
{
    int effic;
    int speed;
}a[100005];
int cmp(Node a,Node b)
{
    if(a.effic==b.effic)
        return a.speed>b.speed;
    return a.effic<b.effic;
}
class Solution {
public:
    priority_queue<int, vector<int>, greater<int>> q;
    _int value =  1000000000 + 7;
    int maxPerformance(int n, vector<int>& speed, vector<int>& efficiency, int k) {

        for(int i=0;i<n;i++)
        {
            a[i].speed = speed[i];
            a[i].effic = efficiency[i];
        }

        sort(a,a+n,cmp);

        _int ans=0;
        _int x;
        _int y=0;
        for(int i=n-1;i>=0;i--)
        {
            ans=max(ans,a[i].effic*(y+a[i].speed));
            q.push(a[i].speed);
            y+=a[i].speed;
            if(q.size()>k-1)
            {
                y-=q.top();
                q.pop();
            }
        }

        return ans%value;

    }
};