20240412-算法复习打卡day52||● 300.最长递增子序列 ● 674. 最长连续递增序列 ● 718. 最长重复子数组

Shiki.2024-04-16 17:01

300.最长递增子序列

从前往后遍历即可

cpp 复制代码

class Solution {
public:
    int lengthOfLIS(vector<int>& nums) {
        if (nums.size() <= 1) return nums.size();
        vector<int> dp(nums.size(), 1);
        int result = 0;
        for (int i = 1; i < nums.size(); i++) {
            for (int j = 0; j < i; j++) {
                if (nums[i] > nums[j]) dp[i] = max(dp[j] + 1, dp[i]);
            }
            if (dp[i] > result) result = dp[i];
        }
        return result;
    }
};

674. 最长连续递增序列

cpp 复制代码

class Solution {
public:
    int findLengthOfLCIS(vector<int>& nums) {
        if (nums.size() == 0) return 0;
        int result = 1;
        vector<int> dp(nums.size(), 1);
        for (int i = 1; i < nums.size(); i++) {
            if (nums[i] > nums[i - 1]) {
                dp[i] = dp[i - 1] + 1;
            }
            if (dp[i] > result) result = dp[i];
        }
        return result;
    }
};

贪心

cpp 复制代码

class Solution {
public:
    int findLengthOfLCIS(vector<int>& nums) {
        if (nums.size() == 0) return 0;
        int result = 1;
        int count = 1;
        for (int i = 1; i < nums.size(); i++) {
            if (nums[i] > nums[i - 1]) {
                count++;
            } else {
                count = 1;
            }
            if (count > result) result = count;
        }
        return result;
    }
};

718. 最长重复子数组

nums1和nums2匹配上之后，dp数组状态只能由其左上角推出来

cpp 复制代码

class Solution {
public:
    int findLength(vector<int>& nums1, vector<int>& nums2) {
        vector<vector<int>> dp(nums1.size() + 1, vector<int>(nums2.size() + 1, 0));
        int result = 0;
        for (int i = 1; i <= nums1.size(); i++) {
            for (int j = 1; j <= nums2.size(); j++) {
                if (nums1[i - 1] == nums2[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } 
                if (dp[i][j] > result) result = dp[i][j];
            }
        }
        return result;
    }
};