第 190 场周赛

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Words count in article: 467 | Reading time ≈ 2

5416. 检查单词是否为句中其他单词的前缀

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class Solution {
public:
    bool check(string a, string b) {
        if(a.size() < b.size()) return false;
        for(int i=0; i<b.size(); i++) {
            if(a[i]!=b[i]) return false;
        }
        return true;
    }
    int isPrefixOfWord(string sentence, string searchWord) {
        stringstream ss;
        ss << sentence;
        vector<string> cot;
        string cur;
        while(ss >> cur) {
            cot.push_back(cur);
        }
        for(int i=0; i<cot.size(); i++) {
            if(check(cot[i], searchWord)) {
                return i+1;
            }
        }
        return -1;
    }
};

5417. 定长子串中元音的最大数目

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class Solution {
public:
    int maxVowels(string s, int k) {
        unordered_map<char, int> mp;
        int curmax = 0;
        for(int i=0; i<s.size(); i++) {
            mp[s[i]]++;
            if(i >= k-1) {
                curmax = max(curmax, mp['a']+mp['e']+mp['i']+mp['o']+mp['u']);
                mp[s[i-(k-1)]]--;
            }
        }
        return curmax;
    }
};

5418. 二叉树中的伪回文路径

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int ans = 0;
    void dfs(vector<int>& count, TreeNode* root) {
        if(root == NULL) return;
        if(root->left == NULL && root->right == NULL) {
            count[root->val]++;
            int f1 = 0;
            for(int i=1; i<=9; i++) {
                if(count[i] % 2 == 1) f1++;
            }
            if(f1 <= 1) ans++;
            count[root->val]--;
            return;
        }
        count[root->val] ++;
        dfs(count, root->left);
        dfs(count, root->right);
        count[root->val] --;
    }
    int pseudoPalindromicPaths (TreeNode* root) {
        vector<int> count(10);
        dfs(count, root);
        return ans;
    }
};

5419. 两个子序列的最大点积

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class Solution {
public:
    int maxDotProduct(vector<int>& nums1, vector<int>& nums2) {
        int n = nums1.size(), m = nums2.size();
        vector<vector<int>> f(n+1, vector<int>(m+1,-5000000));
        for(int i=1; i<=n; i++) {
            for(int j=1; j<=m; j++) {
                f[i][j] = max({nums1[i-1]*nums2[j-1], f[i][j-1], f[i-1][j], f[i-1][j-1]+nums1[i-1]*nums2[j-1]});
            }
        }
        return f[n][m];
    }
};
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