My LeetCode Diary - Day53 Dynamic Programming

1143. Longest Common Subsequence

Link

class Solution {
    public int longestCommonSubsequence(String text1, String text2) {
        int[][] dp = new int[text1.length() + 1][text2.length() + 1]; // 先对dp数组做初始化操作
        for (int i = 1 ; i <= text1.length() ; i++) {
            char char1 = text1.charAt(i - 1);
            for (int j = 1; j <= text2.length(); j++) {
                char char2 = text2.charAt(j - 1);
                if (char1 == char2) { 
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
                }
            }
        }
        return dp[text1.length()][text2.length()];
    }
}

1035. Uncrossed Lines

Link

class Solution {
    public int maxUncrossedLines(int[] nums1, int[] nums2) {
        int l1 = nums1.length;
        int l2 = nums2.length;
        int[][] dp = new int[l1 + 1][l2 + 1];

        for (int i = 1; i <= l1; i++) {
            for (int j = 1; j <= l2; j++) {
                if (nums1[i - 1] == nums2[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
                }
            }
        }

        return dp[l1][l2];
    }
}

53. Maximum Subarray

Link

public static int maxSubArray(int[] nums) {
        if (nums.length == 0) {
            return 0;
        }

        int res = nums[0];
        int[] dp = new int[nums.length];
        dp[0] = nums[0];
        for (int i = 1; i < nums.length; i++) {
            dp[i] = Math.max(dp[i - 1] + nums[i], nums[i]);
            res = res > dp[i] ? res : dp[i];
        }
        return res;
    }