dp11

718. 最长重复子数组

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;
                    result = max(result, dp[i][j]);
                }
            }
        }
        return result;
    }
};

1035. 不相交的线

class Solution {
public:
    int maxUncrossedLines(vector<int>& nums1, vector<int>& nums2) {
        vector<vector<int>> dp(nums1.size() + 1, vector<int>(nums2.size() + 1, 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;
                }
                else
                    dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
        return dp[nums1.size()][nums2.size()];
    }
};

53. 最大子数组和

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

dp

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

392. 判断子序列

class Solution {
public:
    bool isSubsequence(string s, string t) {
        if (s.size() == 0) return true;
        int i = 0;
        for (int j = 0; j < t.size(); j++) {
            if (s[i] == t[j]) {
                i++;
            }
            if (i == s.size())
                return true;
        }
        return false;
    }
};