leetcode周赛 (2020/05/31)

复习期末了，这周周赛水一水

1. 数组中两元素的最大乘积

代码

class Solution {
public:
    int maxProduct(vector<int>& nums) {
        int N = nums.size();
        sort(nums.begin(),nums.end());
        return (nums[N-1]-1)*(nums[N-2]-1);
    }
};

2. 切割后面积最大的蛋糕

代码

const int MOD = 10e8+7;
class Solution {
public:
    int maxArea(int h, int w, vector<int>& horizontalCuts, vector<int>& verticalCuts) {
        
        int N = horizontalCuts.size();
        int M = verticalCuts.size();
        sort(horizontalCuts.begin(),horizontalCuts.end());
        sort(verticalCuts.begin(),verticalCuts.end());
        int maxi = horizontalCuts[0];
        int maxj = verticalCuts[0];
        for(int i=1;i<N;i++)
            maxi = max(maxi,horizontalCuts[i] - horizontalCuts[i-1]);
        maxi = max(maxi,h - horizontalCuts[N-1]);
        for(int j=1;j<M;j++)
            maxj = max(maxj, verticalCuts[j] - verticalCuts[j-1]);
        maxj = max(maxj, w - verticalCuts[M-1]);
        //return maxi;
        return ((long long)maxi*(long long)maxj)%MOD;
        
    }
};

3. 重新规划路线

class Solution {
public:
    int minReorder(int n, vector<vector<int>>& connections) {
        
        vector<vector<int> > con_ind;
        con_ind.resize(n);
         for (int i = 0; i < connections.size(); i++) {
            con_ind[connections[i][0]].push_back(i);
            con_ind[connections[i][1]].push_back(i);
        }
        queue<int> que;
        vector<bool> vis;
        vis.resize(connections.size());
        int ans = 0;
        que.push(0);
        while(que.size())
        {
            int q = que.front();
            que.pop();
            for (auto ind : con_ind[q]) {
                if (vis[ind]) 
                    continue;
                vis[ind] = true;
                int s = connections[ind][0];
                int e = connections[ind][1];
                if(s==q)
                {
                    ans+=1;
                    s = e;
                }
                que.push(s);
            }
        }
        return ans;
    }
};

4. 两个盒子中的颜色数相同的概率